The lockfile format has been changed with release 5.6. Although this does not prevent files from being accessed by earlier releases, you should avoid accessing the same files at the same time with release 5.6 and ealier releases since this will present th following error.
*** A filePro Error Has Occurred ***
On File: W:\ccp/filepro/l_patient_market/lockfile
Old Version of filePro Function Running On This File
File not available. Somebody else is modifying the file; try again later.
You should not get this error unless someone is still in the file with 5.0 or earlier or a program crashed thus leaving the lockfile marked "in use".
Deleting the lockfile will allow you to run release 5.6 or ealier releases without the above message as long as you do not attempt to use 5.6 and earlier releases at the same time.
Caution: Don't delete the lockfile unless you know that no one is using the file.
See FilePro Directory - Option ? for how to unlock a file.