Sigma Articles

Support – File Format or Extension Not Valid

File format or File Extension is not Valid While the “file format or file extension is not valid” error is typical, some users have also reported the error “QuantumXLAddIn.xlam is not a valid add-in” which has the same root cause and workaround.  Root Cause – Windows Defender security setting and misleading error reporting When Attack Surface […]

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Excel Repair and Reinstall

Step 1: Office Repair Microsoft has excellent instructions for how to repair Microsoft Office. They can be found at the url https://support.microsoft.com/en-us/office/repair-an-office-application-7821d4b6-7c1d-4205-aa0e-a6b40c5bb88b or by clicking the button below. If these instructions resolve your issue, then there is no need to proceed further.  Microsoft’s Instructions To Repair Office Step 2: Office Reinstall If repairing Office doesn’t

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