when i try to save changes to a document that i have received from my email as an attachment, it doesn't work. The save or save as window appears to be blank.
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As you have mentioned that the save window appears blank when you try to save file, please try unchecking the box for "Show online storage when saving files".
For that, go to Edit menu > Preferences > General and uncheck the box.
Make sure you click Ok to save settings.
Now try to save file and check if it works fine
Let us know if you need any help.