Hello, I've had 'file format is not valid' issues for the past few weeks which I've just ignored to date but upon investigation, it seems 'someone' has created a duplicate Normal.dotm file. I can still see the original at ..... Roaming\Microsoft\Templates (last modified just under 12 months ago) but there is also a new one on my Data folder created on 12/1/22, (about the time I started using my new Dell laptop and playing around with installing Office). Problem is because this one is within my Dropbox folder it gets synced between new laptop, old laptop, new desktop and old desktop. I've just tried renaming the problem one Normal1.dotm but Excel still points to it and I get the same 'Normal1.dotm file format is invalid' message. So, can I delete it and hope the different versions of Excel and Word will then find the correct file on Roaming\Microsoft\Templates on their respective devices? Thanks Chris by the way, I can't find it now to confirm exact wording but each time I looked in to this, the properties said it was created by Dell (serial number) laptop. Is this significant?