Excel says file is damaged

Hi,

Several times I saved an excel file, closed it, and then later tried to open it. Suddenly I get a notification that Excel doesn't work anymore.

The file goes white and I can't do anything anymore. I tried to repare the file, but Excel says it's damaged.

This has happened several times for no reason. Does someone maybe have an idea how to fix this and/or how I can repair the file?