>>If I recall correctly (and I'm testing it now...) VFP will not allow you to
>>check out a binary file (VCX, SCX, etc.) if someone else has it checked out,
>>even with Multiple Checkouts enabled.
>
>Yes, I tested this, and while the PJM was checked out multiple times (correctly), I could not check a form out on two separate machines at the same time.

Here's the information from KB #Q237847, INFO: The Role of the PJM File in VSS and VFP Integration

The initial limitation of enabling multi-user development of a VFP project is that the VFP project files (.pjx and .pjt) are binary files, and therefore cannot be simultaneously checked out by multiple users. To resolve this, the integration uses the .pjm file, which is a text file. Based on the information in the .pjm file, the integration generates local copies of the .pjx file and .pjt file for each user. It is important that the .pjm file be always checked out to all users.
For the .pjm mechanism to work correctly, you should observe the following guidelines:


Do not add the .pjx or .pjt files to VSS.


Enable multiple checkouts in the VSS administrator.


Never check in the .pjm file.


When choosing "Join Source Control Project" inside VFP, you receive a message that the .pjm is already checked out to another user. Choose Yes on this message. (Note that this is an informational message, not an error.)



If you do not follow these guidelines, you can encounter problems synchronizing the VFP project's (.pjx) contents when one user adds files to, or removes files from the .pjx and other users try to update their local copy of the .pjx.
In chronological order, when you update the project list, the integration component:
Generates a new local project file list (.pjm file).


Checks in the new project file list (with the option set to keep the file checked out).


Merges the local and central project file lists if there are differences. If a merge conflict occurs, VFP displays a dialog box to help you resolve it.


Rebuilds the local VFP project (.pjx) file based on the merged project file list.


Gets local copies of files added to the project by other developers.


Prompts you to get the latest versions of the project files.


Refreshes the display in the Project Manager to reflect changes.




To troubleshoot synchronizing changes to the project file list between users, test for success or failure of each step in turn. Assume that UserA has added or removed files and that UserB is synchronizing his/her local copy of the VFP project (.pjx).

After updating the project list, UserA should open his/her local copy of the .pjm file in a text editor, and make sure that the [Project Files] section has been correctly updated. If not, the usual cause is that the .pjm file is read-only.


Compare the latest version of the .pjm file in VSS with UserA's local copy. You can do this either by viewing it from within the VSS Explorer, or by choosing "Show Project List Differences" from the Project, Source Control menu. The files should be identical. If not, try checking the file in from within the VSS Explorer, with the option for "Keep checked out" checked. Make sure that you can successfully check the file in.


UserB should repeat the test from step one.