Someone else has already signed on with the same User ID...
If you haven’t already done so, we suggest you read the Troubleshooting Alert Messages Overview.
Situation: A person at a different workstation has already opened this data file with the user ID that you entered in the User ID field of the Sign-on window. A user ID can be used by only one person at a time.
Solution: Either enter a different user ID in the User ID field of the Sign-on window or wait until the person using the user ID you wish to use closes the data file.
If nobody else is currently using the user ID you wish to use, it’s possible that the data file was closed incorrectly the last time this user ID was used. If this is the case, all current users of the data file must close the data file and then reopen the file. You should then be able to open the data file with this user ID again.