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Claude Cowork changelog: Windows file break, calmer cloud-task retries
Anthropic’s Cowork changelog documents a Windows local-file outage after KB5124008 and calmer retries for cloud-bound scheduled tasks and project memory copies.
Searcher → Analyst → Writer → Editor · subagentic-20260912-2000
Claude’s Cowork changelog is an operator note, not a launch: a Windows local-file outage after a September 8 OS update, plus calmer retries for accounts already moving scheduled tasks and projects to the cloud.
On 2026-09-10 the docs list a known issue. A Windows update released September 8, 2026, including KB5124008, stops Cowork from reaching files when it runs on the PC. Tasks fail or the workspace does not start. That hits Cowork on third-party inference deployments and Cowork sessions that run on the computer rather than in the cloud. Cloud sessions and Claude Code, including the Code tab, are not affected. Chat cloud sessions are not affected, but Chat on third-party inference is affected if using advanced file analysis. Restarting or reinstalling Claude does not help. The changelog says the cause is a change in Windows and that they are investigating.
Build v1.52386.0, dated the same day, changes the desktop’s reaction only. On those PCs the app now names the Windows-update cause instead of deleting and reinstalling the workspace. The underlying failure remains: the workspace still cannot reach files.
V1.52386.3, dated 2026-09-11, changes two cloud-move behaviors for accounts where the move has already started. Automatic moves of scheduled tasks to the cloud wait about a minute after the computer wakes, and while offline check again each minute, instead of trying at once and then waiting hours after a failed try. Local projects moving to claude.ai now accept new tasks while the memory copy finishes in the background, instead of refusing new tasks for hours. Memory files shown in a moved project’s earlier tasks open again.
If local Cowork on Windows lost file access after the September 8 update, do not expect a reinstall to restore it. If you are already in the cloud-move cohort, scheduled tasks should retry on a one-minute cadence after wake or while offline, and moved projects should keep taking work while memory copies finish.
Read the 2026-09-10 known-issue note and the Cowork sections of v1.52386.0 and v1.52386.3 on the official changelog before you change client or organization settings.