Photoshop 27.6.0 nearly unusable on macOS 26.4.1: apparent scratch disk misread of APFS purgeable space

Hey everyone, Photoshop 2026 is running as if it’s severely disk-constrained on a machine that has >240 GB of available storage on the startup volume. Performance is unusable, multiple-second delays on tool selection, UI interaction, even basic text editing.

Root cause hypothesis
macOS APFS reports two distinct storage figures:
- diskutil data volume: >59 GB truly free
- Finder / macOS storage APIs: >240 GB available (free + purgeable)

Purgeable space is APFS-managed storage that macOS can and will reclaim on demand, it is not inaccessible. Apps querying disk space via standard macOS APIs (NSFileManager attributesOfFileSystemForPath) should receive the Finder-inclusive figure (~240 GB). If Photoshop is instead reading the raw diskutil figure (~59 GB), it would incorrectly treat the machine as disk-constrained.

Operating environment
Hardware: M3 MacBook Air, 24 GB, 1 TB internal SSD (APFS)
OS: macOS Tahoe v. 26.4.1
Photoshop: v. 27.6.0
Scratch disk: startup volume (default)
Subscription: Creative Cloud Pro

Reproduction steps
1. Machine: as described above
2. Fresh reboot, no third-party processes running (aside from Adobe’s)
3. Launch Photoshop 2026 as the sole application
4. Open a .jpeg and try using a selection tool, heal brush, add and modify text layers
5. Observe: severe UI lag across all interactions:  tool selection, brush strokes, panel updates

What I've ruled out
- Memory pressure (24 GB RAM, confirmed via Activity Monitor: no swap, no memory pressure)
- Competing background processes (isolated to Adobe services only post-reboot)
- Scratch disk misconfiguration (set to Data volume, same APFS container as system; the expected default)
- Tried setting scratch disk to an external SSD over USB4 with >300 GB free: problem was worse
- Hardware fault (all other apps including other Adobe apps perform normally)

APFS purgeable space is standard behavior on every modern Mac. It’s especially prevalent on machines with iCloud Drive enabled, which is a very large portion of the Creative Cloud user base. If Photoshop is misreading purgeable space as unavailable, this bug affects any Mac running Tahoe with a meaningful iCloud footprint, regardless of actual free storage.

Can the team confirm which disk space API Photoshop uses to evaluate scratch disk headroom, and whether that path correctly accounts for APFS purgeable space under macOS Tahoe? Happy to run any diagnostics, provide system reports, or test builds.