Windows11 Clipboard history does not sync across devices despite being enabled

You have clipboard history enabled on both Windows 11 devices under the same Microsoft account, but cloud synchronization stops again after a sign-out fix. First verify on each PC under Settings > System > Clipboard that “Clipboard history across your devices” is on and “Automatically sync text that I copy” is selected; manual mode requires choosing Sync for each item in Windows+V. Test with plain text, because each clipboard item is limited to 4 MB and cross-device troubleshooting should exclude format-specific content. Press Windows+V and clear unpinned history on both PCs, then use Clear under Clipboard settings to clear the cloud copy. Toggle the cross-device setting off, restart both PCs, turn it on again, and retest. If it still stops after several hours, record both Windows build numbers and the failure time and submit Feedback Hub diagnostics; the recurring authentication behavior is not explained by a local clipboard-size limit