An old customer from Buckingham (Oxfordshire) contacted us with an issue. He could not open any Microsoft Excel or Word files on his personal Windows 10 PC. With Excel, it would simply open an empty Excel Window, with Word, it would pop up a not particularly meaningful error message. Multiple reboots weren’t helping.

I connected via TeamViewer and quickly discovered that the whole Windows system was misbehaving. The most worrying issue was that I could not launch any applications or system components that required administrator rights. For example, trying to uninstall any application would throw the following error message:

This kind of system errors can be caused by corruption within the file system or a failing hard drive. System logs, however, were not displaying any such issues. There also were no obvious evidence or a malware infection.

I then checked the status of Windows updates. Windows 10 itself was on the latest major version (22H2), however, there were some pending updates (.NET Framework, something related to Microsoft Office, and a cumulative Windows 10 update). The last one, was in failed status, other two were pending installation. After installing all 3 updates and rebooting the PC everything was back to normal. File system errors were gone and Microsoft Office was functioning normally as well.