Welcome to Seven Forums alwyn. Did you downgrade from Outlook 2010 for instance? Here is a way to just delete the profile key in your registry if you don't want to go through the trouble of creating a new profile. The mail profile was created with a newer version of Outlook | MSOutlook.info
Always a good idea to backup the registry just in case, but seems very straight forward. There is a download
for using the default Outlook profile name as well, so you don't have to edit manually. Registry - Backup and Restore
P.S. Downloaded the reg file and scanned it, all is safe. Looked at the file and it is legit. Just download, double click on it, ok when asks if want to merge. I would restart PC after just to make sure.