problems using "Modifiying EXIF date and time"

[CollieDog]

Hi!
I've forgot to set my camera date and time on recent trips and this leads to confusion later! Dumb!

Even more confusing is the fact that on my computer (had same trouble with Window 7 as now with 8.1), the OS displays the date created or modified. Even when I select "Date Taken" the dates often seem to be messed up and confused. Only IMatch can be trusted for displaying the actual date and time  the photo was taken. I've become really quite confused the amazing inconsistencies of Windows.

I've used the "Modifiying EXIF date and time" many times before, but after wiping my system and upgrading to Windows 8.1, I'm unable to use it.
Each time I try to change the date of a photo, I receive this error "blaablaa IMatch is not allowed to update this data"

I really don't want to mess up my database during future imports and so want to ask before I change any default settings.
Should I go into PREFERENCES--- METADATA2 --- SETTINGS --- KEEP EXISTING XMP  and change it to NO?

I'll wait for a reply before I dare do anything! 



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[Mario]

Go to Edit > Preferences > Metadata 2: File Formats.
Select the file format you are trying to update and make sure that the options to allow EXIF updates is set.