I don't know what's going on.
thousands of my pictures had their dates changed to now/2021. I had to change back thousands, but many shows up with 2021 dates everyday.
The only app that changes my photo's properties and tags are Windows/Onedrive and iMatch.
Is there a way to protect/lock some tags when I first bring them to my computer ?
I'm really lost here.
Which date has changed? Do your files contain valid date and time information in the EXIF record?
If there is no usable date, IMatch uses the older of the "created" or "last modified" date and time reported by Windows, and these dates will change when you update or copy the files (e.g. via OneDrive).
You need to set the timestamps once in IMatch and "persist" them by writing them back into metadata.
IMatch does this automatically by default when the option Edit > Preferences > Metadata2: Mark file as pending write-back is enabled (default).
If you don't write-back the file once, the next time IMatch has to re-import it (e.g. because the last modified timestamp on disk changes), the date will be updated to whatever is now in the file system.
Please read this help topic for full details: How IMatch uses Date and Time Information (https://www.photools.com/help/imatch/#tech_exifdate.htm)