The save failed due to out of memory or disk space

Update Office for Mac first, because Word’s save process depends on creating and replacing temporary files, and Microsoft’s current Word for Mac notice identifies an update-related reduced-functionality condition that can prevent files from being edited, created, or saved.^1^^2^

1. Update Word and protect the open documents

1. In each document containing unsaved work, select all content and copy it into a new blank document as a temporary safeguard. This is a documented troubleshooting approach for this specific Word error.^3^
2. In Word, select Help → Check for Updates.
3. In Microsoft AutoUpdate, select Check for Updates, install every available Office update, and enable automatic updates.
4. Restart the Mac after installation.
5. Open Word and test:
   • A new blank document saved to a local folder outside OneDrive.
   • One of the affected existing documents.
   • The same document saved under a new name.

The error does not necessarily mean that the Mac has run out of space. Word creates a temporary file during saving and then replaces the original; interruption of that process can produce disk-space or write-protection messages even when storage is available.^1^

2. Check activation and file access if updating does not fix it

Since the problem affects multiple documents and locations, check Word itself rather than repeating disk tests:

1. Select Word → About Microsoft Word and verify that Office shows as activated.
2. If Word can open and print but cannot edit, create, or save files, sign out of Office, restart the Mac, and sign back in with the account that owns the Microsoft 365 subscription or Office licence. That pattern is consistent with reduced-functionality mode.^2^
3. In Finder, select an affected document and choose File → Get Info:
   • Clear Locked, if selected.
   • Under Sharing & Permissions, ensure your macOS account has Read & Write access.

A locked file, unavailable write permission, or blocked folder access can prevent Word from saving even though sufficient disk space exists.^4^

3. Isolate the macOS profile

If Word is updated and activated but every save location still fails:

1. Open Apple menu → System Settings → Users & Groups.
2. Create a temporary macOS user.
3. Sign into that account, open Word, and test saving a new local document.
4. If saving works there, the fault is confined to the original macOS profile—typically its Word preferences, permissions, or Office user data—rather than the documents or disk.^5^

If saving also fails in the temporary account, reinstall Office from the Microsoft account associated with the licence. Preserve copies of any unsaved document content before uninstalling.

Do not reset OneDrive unless Word saves locally and fails only inside OneDrive. Resetting OneDrive can remove unsynced local content, so it is not appropriate while the failure also occurs in other locations.

References

1. There is a serious disk error on when attempting to save, copy and paste or create auto recovery files in Office for Mac
2. Fixes or workarounds for recent issues in Word for Mac | Microsoft Support
3. Cannot save file due to 'The save failed due to lack of memory or disk space.' - Microsoft Q&A
4. Why has Word suddenly no allowing me to save or save as my document? The options are grayed out. - Microsoft Q&A
5. Word, Excell won't save documents - Microsoft Q&A