Hello,
Thank you for posting in Microsoft Q&A.
Based on the description, I understand your question is related to unable to open / export protected excel documents.
Ensure that Excel is set as the default program for opening .xlsx files. You can do this by right-clicking on an Excel file, selecting "Open with," and then choosing Excel. Make sure to check the box that says, "Always use this app to open .xlsx files."
In Excel, go to File > Options > Advanced and scroll down to the General section. Check the box for "Ignore other applications that use Dynamic Data Exchange (DDE)". This can sometimes resolve issues with opening files.
Also, according to the error message, you need to check that your system has enough available memory and disk space. After that, install the latest windows update and check Office updates.
Have a nice day.
Best Regards,
Molly
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