It sounds like when you re-installed filemaker after the system rebuild you accidentally used the same install code as one of the other machines on your network. That would explain the error you are seeing anyway.
All I did was copy the program to a disk and copied it back so all the info remained the same. It worked fine before the OS upgrade. I have done the same to two other computers and it works fine. I have thrown away the FM preferences as per the instructions on the site but it still does not work. I can open another DB that is on another computer and it opens fine.
Thank you for your post.
When FileMaker Pro launches, it takes the installed License Key and looks on the network to see if that License Key is in use by another machine. If so, then you get the message. In your case, it found the License Key conflict with user "Dennis Morrison". Therefore, disconnect yourself from the network, launch FileMaker Pro, pull down the FileMaker Pro menu and select "About FileMaker Pro". This will display the installed License Key. Then, go to Dennis Morrison's computer, launch FileMaker Pro, and verify he is using the same License Key. If not, then reconnect yourself to the network, and launch FileMaker Pro again.
Let me know if you continue to run into difficulty.
I just started getting this error out of nowhere in the last few days & I'm baffled, particularly since it says that the conflict is with myself. I'm the only user at my office using the Developer version of FM6 (for an old, very complicated & always in use database), so I really don't know what happened. I could try reinstalling it, but I'd like to purge the current license key first & I can't figure out where that's held. I really need to get this sorted out so I can get back into the Budget database (on our server, so disconnecting from the network isn't an option).