Saving your Office 365 files should be a simple process.
So, kindly save the file using a different name and then close it.
kindly dont use special characters in the filename; keep it short and simple.
Ideally, use a two or three-letter file name.
Many users confirmed this simple workaround did the trick for them.
Hopefully, using a temporary save name works for you as well.
Then see if you’re able to store your files without getting the invalid filename error.
Select a different drive to back up your file and find out if the error is gone.
Update and Repair Office
verify youre running the latest Office version on your machine.
Launch any Office app, navigate toFile, select your account, and hit theUpdate nowoption.
Speaking of updates, do implement the latest Windows 10 OS updates on your machine as well.
Go toSettings, selectUpdate & Security, click onWindows Updateand check for updates.
If the error persists, then maybe your Office files got corrupted, and you better repair them.
