Posting this in case others are seeing unexplained high memory usage on Windows with iCloud installed, and to document the diagnosis in case it's useful to Apple engineering. Environment: Windows 11, 32 GB RAM, AMD platform, NVMe SSDs. iCloud for Windows with iCloud Drive, Photos, and Keychain in use. Symptom: Memory usage climbed to ~91% (28+ GB "in use") with no user-mode process accounting for it. Task Manager's process list only summed to a few GB, so the memory was being held somewhere the process view doesn't show. Diagnosis:
RAMMap showed nonpaged pool sitting at ~21 GB. That's abnormal — nonpaged pool is normally a few hundred MB. poolmon isolated it to the NTFS "NtFC" (file-context) pool tag: ~51.3 million allocations against only ~12,000 frees, roughly 18.4 GB outstanding. That allocations-far-exceeding-frees pattern is a classic handle/file-context leak. The NtFC tag is owned by ntfs.sys, which means something above the filesystem was opening file references and never releasing them. iCloud was the only cloud client running its full process set (iCloudDrive, iCloudHome, iCloudCKKS, FileCoAuth) alongside the Windows cloud files filter driver.
Behavior: By the time I checked, the leaked count was frozen rather than actively climbing, which suggests it accumulates during sync/enumeration activity rather than continuously. Note that leaked nonpaged pool is not reclaimed when you kill the processes — those allocations persist until reboot. Workaround / fix: Uninstalling iCloud for Windows and rebooting cleared the ~18 GB and returned memory to normal. Post-reboot, with OneDrive and WSL still running, usage settled around 32% and stayed stable, which points to iCloud as the source. Has anyone else run into this? Curious whether it correlates with a specific iCloud version, iCloud Photos being enabled, or large-folder sync. Would be good to get this in front of Apple if it's reproducible for others.