Release Notes

Background workers no longer appear in the app switcher

• Fixed Lumen showing up many times in Cmd-Tab. The metadata and thumbnail workers split out in 0.5.16 and 0.5.17 were registered as ordinary apps, so with eight thumbnail workers running you got eight icons in the switcher. They are now marked background-only and appear in neither the switcher nor the Dock.

Thumbnails are built in a separate process too

• Thumbnail building moved to a lumen-thumb-bg worker. It gains more from isolation than metadata did: the thumbnail path falls back to QuickLook, which on a wedged mount never returns at all. In-process there was no way to reclaim a lane pinned like that; now a worker that stops answering is killed, the photo is recorded, and the pass continues.
• QuickLook is no longer called for files that aren't there. It waits up to 15 seconds per call, and a disconnected folder is thousands of missing paths — enough to stall the whole pass by itself. Those are now reported immediately as unreachable.
• Decode buffers now accumulate in the worker rather than the app, and go away when it exits.

Metadata is read in a separate process

• Photo metadata is now read by a helper process, lumen-meta-bg. The system image decoder can abort the whole process on a malformed file — which used to mean Lumen itself died mid-browse and lost the pass. Now only the helper dies, the file that killed it is recorded by name, and indexing resumes at the next photo.
• Being able to name the offending file is the real win: open the metadata item in the status bar to see the list with reasons, and retry.
• If the helper is missing, metadata is read in-process exactly as before — the feature degrades, it never disappears.

Fixed thumbnails never being built at all

• Folder-watcher rescans no longer overlap. A rescan walks the entire library — 107,000 photos across three SMB shares on the reference machine — and filesystem events arrive far faster than that finishes, so passes piled up: 13 concurrent walker threads, 37% CPU, 3GB resident, and not one thumbnail produced, because each new pass restarted the thumbnail work before the previous one could finish anything.
• Thumbnail restarts are coalesced too. Sizing a pass hashes every photo in the library (~3s at 107,000), so a run of library changes spent all its time re-sizing the work and none doing it.
• A change that lands mid-scan is replayed once afterwards rather than lost.

Refresh the Photos library

• Photos added or deleted in Apple Photos now show up. The library was read once at first open, so anything you changed in Photos afterwards stayed invisible until Lumen was relaunched. Changes are now picked up automatically, with rapid ones coalesced into a single re-read.
• You can also refresh on demand — right-click Photos Library in the sidebar, or press ⌘R. The album you have open is re-read too.

Export a whole album or library, with progress and a stop button

• Right-click to export from the sidebar. The entire Photos library, a single Photos album, or a Lumen album — each offers originals, 2048px resized copies, or a zip. Folders already did; the same menu now means the same thing everywhere.
• Exporting is a tracked job you can watch and stop. It used to be fire-and-forget with a toast at the end — fine for a few photos, useless for 71,000 where every iCloud-only asset downloads first, and indistinguishable from a hang. The status bar now shows Exporting 1,204 of 71,631 with a progress bar; click it for detail or to stop. Files already written are kept.
• A Photos album can be exported without opening it first — its contents are fetched on demand.

Photos-library pictures can be exported

• Export originals, resized copies and zips from your Apple Photos library. The Export menu appeared but did nothing there — a Photos picture has no file on disk to copy. Lumen now pulls the real bytes out of PhotoKit, downloading anything that lives only in iCloud. Edited photos export the edited version, the one you actually see.
• Photos allows many pictures to share a filename, so exports that collide are numbered rather than dropped.
• The sidebar's "Albums" row opens on a single click. It needed a double click, and even that was frequently swallowed, so clicking it looked like it did nothing.

The sidebar tells local, external and network folders apart

• Added folders now show which storage they live on. Internal disks keep the plain folder icon, external drives get a drive icon, and NAS or network shares get a drive icon with a wireless badge — a folder that takes minutes to open no longer looks identical to one on the internal SSD.
• The badge appears on the roots you added, not every descendant: repeating it down the tree is noise, and the top level is where the storage boundary actually is. Hovering names the volume, e.g. "Network share · zpool".

Metadata is no longer re-read when a volume moves

• The volume identity introduced for thumbnails in 0.5.9 now covers the metadata index too. A share reachable at a different mount point used to mean re-reading EXIF for every photo under it — tens of thousands of files, hours over a NAS. Entries filed under the previous path are now adopted without touching the file.
• Nothing is ever discarded to achieve it. Rather than re-keying the index, the match happens at lookup time: if a share simply happens to be unmounted at launch, its entries must not vanish — that would turn a cosmetic problem into a 64,000-photo re-read. Old-path records are cleaned up only once the same file is confirmed under a live path.

A NAS that moves mount point no longer rebuilds the cache

• Thumbnails survive the same share being mounted somewhere else. Cache keys used the absolute path, so a share seen as /Volumes/zpool on one login and /Users/…/nas-mnt/zpool on the next invalidated every thumbnail under it — measured 101,599 files on disk with only 33,198 still reachable. Volumes are now identified by themselves (UUID for local disks, the share address for network mounts), and existing thumbnails are adopted rather than rebuilt.
• Metadata progress shows the actual work. A pass with 8,445 photos left to read displayed "55,809 of 64,254", which read as re-doing everything every time. It now reports the pass's own work, with the already-cached count as context in the detail popover.
• Thumbnail progress shows throughput and time left — 2.4/s · ~3.6h left.
• Faster thumbnail building over a NAS. Network reads are latency-bound, so concurrency went from 3 to 8 lanes there (local storage stays at 3).

The detail popover updates live, and jobs can be restarted

• Fixed the detail popover showing frozen numbers. It kept displaying the values from the instant it opened — "Idle" and a progress bar that never moved — while the job was plainly running. The file being read and the progress now update live, and a job that has just started says "Starting…" rather than "Idle".
• Fixed status-bar text spilling vertically in a narrow window. When space ran short the text wrapped one character per line and grew straight out of the status bar over your photos. Rows now stay on one line and shorten the folder name and rate first.
• Jobs can be restarted. In the detail popover, "Restart" re-runs the pass over whatever is still missing, and "Rebuild All…" discards the cache and starts from zero (it asks first — that one takes hours).

Click a background job for details — and retry the photos that failed

• Status-bar jobs are now clickable. The popover shows the exact file being read (full path), the progress and throughput, and the photos the job could not process — each with the reason and a reveal-in-Finder action.
• Failed photos are recorded and can be retried. Nothing used to record them, so a thumbnail that would not decode simply stayed blank and unreadable metadata stayed silently empty. Failures now persist across launches, with a reason, and "Retry" runs them again.
• A count badge appears on the row when anything failed, and stays after indexing finishes — a partial failure is no longer reported as success.
• Fixed overlapping text in the status bar, where a long job row was drawn straight through the centered item count, and a progress counter that could exceed its own total.

A disconnected drive can be removed from the library

• Folders on a NAS or external drive that is gone can now be removed. Those rows were grayed out and refused both selection and right-click, so a drive that never came back stayed in the sidebar for good. Right-click now offers "Remove from Library" — it only forgets the folder, never touches files, and adding the folder back undoes it.
• Fixed a folder rendering grayed out after being added back at the same path as a previously removed one.
• Removing a folder while its drive is dead no longer freezes the app — checking the remaining folders moved off the main thread.

Adding a large folder responds right away

• Add a 30,000-photo folder on a NAS and photos start appearing immediately. Previously nothing showed until the whole folder had been read — minutes over SMB. Results now stream in folder by folder, the count of photos found climbs live, and you can stop at any time.
• Re-adding the same folder, and the next launch, no longer re-read the whole tree. Folder timestamps are recorded during the import, so the per-file network round-trips are gone.
• Background work now shows how much of the total is done. Thumbnail caching and metadata indexing report 12,340 / 30,124 with a progress bar instead of counting down with no denominator.
• The app stays responsive during an import. Filesystem probes and the library merge moved off the main thread, and folder-watcher rescans are held back while an import runs so they don't compete for NAS bandwidth.

Favorites, tags, and labels open instantly

• Removed the ~0.1s stall when entering Favorites · On This Day · Labels · Tags · Albums · Duplicates on large libraries. The membership scan moved off the main thread, so entry is instant and rapid favorite/rating edits while culling no longer hitch — measured 94ms → 0.09ms.
• Built-in instrumentation probe (dev-only, fully inert normally) now verifies performance on every release; the landing-page benchmarks come from its real-library measurements.

The thumbnail cache never resets again · instant paint instead of empty cells

• The thumbnail store moved where macOS can't purge it. Under storage pressure (or with cleaner apps) the system wiped the cache folder wholesale, forcing tens of thousands of thumbnails to rebuild from scratch. Existing caches migrate automatically.
• Uncached photos paint immediately instead of sitting as empty gray cells. The photo's embedded preview draws first (a header-only read), then the sharp thumbnail swaps in — biggest on iPhone HEICs.
• Old cache orphans left after moving a library to another drive (gigabytes) are garbage-collected once a day. Fresh entries and disconnected-drive caches are never touched.

Disconnected-drive guard · faster loading while the cache rebuilds

• When a NAS or USB volume disconnects, its folders gray out in the sidebar and can't be clicked. Your photos and organization are preserved, and everything comes back automatically when the drive reconnects.
• Visible photos load much faster while the thumbnail cache rebuilds (after moving a library or clearing caches): background caching now fully yields until on-screen decodes finish, and duplicate reads of the same original (up to 3× I/O) are gone.
• Editing rotated photos uses half the memory on save — large panoramas are safe to edit on low-RAM Macs.

Hotfix: crash when showing a notification

• Fixed a critical crash the moment the first in-app toast appeared (export finished, update check, and similar). 0.5.0's localized-resource lookup only worked on the development machine and always failed on user machines. Resources are now resolved from the right location, and if they're ever missing the app falls back to default English text instead of aborting. Thanks to the crash reports that pinpointed this (#5, #6).

Major performance pass · stronger data safety

• No more hitches after editing, deleting, or culling. Favoriting/rating/deleting no longer stalls the sidebar, folders, or search (derived data is recomputed off the main thread). Deleting photos one by one stays smooth.
• Smoother scrolling. Thumbnail decoding moved off the main thread, and a fast first sweep over a NAS no longer lets off-screen cells' decodes block the cells you actually land on.
• Faster viewer paging. The photo you're looking at no longer waits behind neighbour pre-loads.
• Search, map and camera filters are ready ~0.5s sooner after launch (the EXIF index now uses a fast binary cache).
• Stronger data safety. Fixed duplicate-finder false positives (which risked deleting a unique photo), folders vanishing on a transient NAS hiccup, and a cleared library reappearing on relaunch. Edits and exports now preserve capture date and location (EXIF/GPS).
• Large-library correctness. After a sort settles, map pins, selection order, and post-delete selection no longer show stale state.

Grid reflow · album speed · small polish

• Apple Photos albums re-open instantly. Re-entering an album used to re-query PhotoKit every time; it's cached now, so going in and out stays fast. (NAS folders were already instant — 0.4ms.)
• Fixed the grid not re-flowing when you widen the window. Columns now re-lay out to fit the window size.
• On This Day, when empty, shows a friendly note instead of a blunt "No Photos".

Deletion safety net — undo, even on a NAS

• Deleting on a volume with no Trash (NAS/SMB) is no longer permanent. Files move to a hidden .LumenTrash folder on the same volume (an instant rename), purged automatically after 30 days.
• Every delete shows a 10-second Undo button that restores the files — and their favorites, ratings, and album memberships.

Crash reporting — privacy intact

• A crash writes a report with only the version, OS, and stack trace to your Mac; the next launch offers to open a prefilled GitHub issue. Nothing is ever sent unless you choose to — no file paths or photo data are in the report at all.

Performance — bulk operations

• Favorite/rate/label/tag a big selection in one transaction. Favoriting 20,000 photos: 0.4s (was one commit per photo — minutes).
• File work for delete, undo, batch rename, and export all runs in the background — hundreds of NAS photos no longer freeze the UI.
• Renaming a folder no longer recomputes paths in a way that could hang a 60k library for minutes.

Fixed

• A sync race where a delete/undo finishing mid-NAS-scan could be reverted.
• EXIF info for photos deleted during a long indexing pass coming back.
• The slideshow-interval setting now actually applies, and the default sort persists across launches.
• Failed metadata writes (full disk etc.) now show a notice instead of being silently dropped.
• A one-time culling-shortcuts hint (Space/X/1–5) on first viewer open; toasts follow the system language (English/Korean).

Performance — bulk album operations

• Adding/moving photos into a large album is instant now. Adding 10k photos to a 20k-photo album froze the app for 10 seconds; it's ~0.2s now — only the added rows are written instead of rewriting the whole album. Photo order is preserved.
• Bulk removal too. Removing 10k of 20k: 7.6s → 17ms.
• ⌘C no longer stalls. Image data for a copied NAS original was read on the main thread; it now loads in the background — the file path copies instantly and the image data follows when ready.

Sidebar folder tree, Finder-style

• Clicking a folder always selects it and toggles its children. Clicking an expanded folder while browsing another album now folds it immediately — no second click, no swallowed clicks (input was rewritten at the AppKit event level).
• Keyboard navigation is calm now. ↑/↓ only move the selection — folders no longer unfold as you arrow past them; → reveals the selected folder's children, ← folds them.

Fixes

• Favorite/label counting sent a per-photo round-trip to the NAS — large favorite sets could freeze the main thread.
• Thumbnails and badges went blurry after moving the window to a display with a different scale.

Performance — your photos are just there when the app opens

The launch path was redesigned, measured frame-by-frame against a 67,676-photo library.

• The launch loading state is gone. The window appears with a fully populated grid — thumbnails included — within a frame or two. Previously a "Loading your photos…" spinner sat on screen for ~1.4 seconds.
• New binary library cache — decoding 67k photos went from 410ms to ~100ms. Your existing cache migrates automatically on first launch.
• Sorting, stats, and search indexes are all precomputed in the background, overlapping the window construction time — and the first screenful of thumbnails is pre-warmed into memory before first paint.
• The loading indicator now only appears when loading genuinely takes long (first scan, cold NAS).

Performance

A large performance batch, measured and fixed against a real 67,676-photo NAS library.

• Selecting photos is instant. Inspector updates went from ~70ms per click to ~3ms; Select All on 67k photos went from an 800ms freeze to ~0.2s.
• Search no longer freezes the UI. Filtering a large library (~0.4s per search on the main thread) now runs in the background alongside the sort.
• Removed a 3–4 second freeze ~40 seconds after launch — the library reconcile and the thumbnail-cache warm-up scan were blocking the main thread.
• The thumbnail-size slider and window resizing are smooth now. Grid thumbnails are GPU-scaled instead of being re-rasterized on the CPU (~350ms per tick before).
• List view is now a native table — opens instantly with tens of thousands of rows, and large selections are ~5x faster.
• First folder click after launch 156ms → 4ms; first-search and launch-time hiccups trimmed by precomputing the library indexes.

Fixes

• Deleting photos now works on NAS volumes. SMB shares have no Trash, so deletion silently did nothing; Lumen now warns Finder-style ("deleted immediately") and deletes in place. NAS-side recycle bins (e.g. Synology #recycle) still catch it, and failures surface a toast instead of vanishing.
• Backspace/Delete actually delete in the viewer, list, and month views.
• Switching folders starts at the top instead of keeping the previous scroll position; deleting/importing in place still keeps your spot.
• Folders with subfolders select correctly (accent highlight) on a single click and reveal their children every time; re-clicking folds them.
• Corrupt image files (zero-filled failed copies) show a warning mark instead of masquerading as a generic JPEG icon — and no longer poison the thumbnail cache.

New

• Closing the window no longer quits. Thumbnail cache warming continues at a trickle (under 1% CPU, one decode every few seconds) and returns to full speed when you reopen the window. ⌘Q quits as usual.

• Folder tree: clicking a folder with subfolders selects it and toggles its children — expand on the first click, fold on the next (Finder-style).

Performance

• Thumbnail loads no longer stat the original file — one NAS round-trip saved per photo while scrolling.
• Viewport-driven prefetching follows the scroll direction instead of decoding the whole list up front.
• Two-tier thumbnail cache: small grid cells use a 256px tier, fitting ~4x more thumbnails in the memory cache (no more cache thrashing on dense grids).
• The monthly timeline no longer regroups the whole library on every redraw.
• Large albums sort off the main thread like every other view.
• Background cache warming starts with the folder you're currently viewing.

Fixes

• Folders with subfolders select on a single click in the sidebar.
• Grid ←/→ keys wrap to the next/previous row at row ends (Finder-style).

New — update notifications

• Lumen checks for new versions automatically (once a day) and shows a banner when one is available. Check for Updates… in the menu works on demand.
• Homebrew installs get the upgrade command; direct downloads get the release page (no auto-install, so it never fights Homebrew's version tracking).
• The cask gained livecheck — brew outdated / brew upgrade detect new versions reliably.

Search & indexing

• Camera/EXIF search — search by camera name (e.g. "SONY"). The EXIF index builds itself in the background (local disk first, then NAS).
• Indexing progress shows in the status bar, with a checkpoint every 2,000 photos so a relaunch resumes where it left off.

Apple Photos / iCloud

• Selecting a Photos-library photo shows its metadata in the inspector (dimensions, kind, size, camera EXIF, GPS).

Browsing & editing UX

• Home/End/PageUp/PageDown keyboard navigation in the grid.

• First public release — local & NAS folder libraries, grid/list/map views, non-destructive editing (crop, rotate, combine, watermark), favorites/labels/tags/albums, Homebrew cask distribution.