I try to apply all updates regularly but don't remember when the last program update was. Yesterday, I began having the same problem with all my excel spreadsheets in my OneDrive folder on my computer. The folder is synced to OneDrive, so I can use it offline. I encountered the same problem when not connected to the internet. Last week I used these spreadsheets and had no issues. I devised a workaround by copying the spreadsheets to another folder on the computer not inside the OneDrive folder. I can then access the copied spreadsheet normally without problems.
Today I followed-up on this, accessing the forums and found this thread and the one about excel (topic 264962) referencing this topic. When I applied the workaround (actually clicking on the "restore defaults" tab) the workaround seems to be working for me as well. I also had not made any changes to the advanced settings, but I did notice that applying the "restore defaults" tab turns off the "block penetration testing attacks" tab on the first page of the Settings - Security section. Later, I will see if turning this back on creates the problem again.
Also, some of my spreadsheets may have URLs in them but not all of them. I didn't notice any problems with Word documents but I do not access them often and this problem only began yesterday. I will check with Word also if my test with the "block penetration testing attacks" tab actually recreates the problem. I am attaching screenshot of my version information.
