OK. This is a common enough problem and this thread is practically in syndication without a proper answer, so I felt it was necessary to respond.

THE IMPORTANT THING IS TO SAVE THE SOLUTION IMMEDIATELY AFTER OPENING IT FROM SOURCE CONTROL!!!

If you have not done this, you must delete all the files and start over. The follow instructions solved the problem for me. I had read this before and didn't believe it, so I'm including a bunch of other info for anyone who is as stubborn as me. Maybe you'll find another way to do it.

1. delete all files in project and related files (search using "show hidden files" under advanced options to find everything).
2. open from source control
2a. I had to go to windows explorer and all the properties of the files with the same name as the .sln and unclick the "read only" checkbox.
2b. I had to convert the sln to my current .net version
3. right click on the .sln in the solution explorer and save - at the dialog box, select the overwrite option

Wow! after much experimentation, I was able to close the solution, open it and it was still bound to source control!
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IF you choose to try it without deleting files, read the following first:

I found some explaination at this page ( http://support.microsoft.com/kb/317957 ), which was very helpful; howver, as usual, the microsoft canned solution bears little resemblance to the product it refers to.

specifically:
RESOLUTION
1.Change source control to unbind and then rebind to the original location. To do this, follow these steps:
1. On the File menu, click Source Control, and then click Change Source Control.
2. When you receive a prompt, save the solution. The Change Source Control dialog box appears.
3. Unbind and then rebind to the original location. The following dialog box appears:
Some projects have been bound to server locations that may be incorrect. A location may be incorrect either because it does not contain the

majority of the projects' files or because those files are not in the correct location relative to the specified server folder. You should probably fix all the bindings in the solution. However, you may continue and bind these projects to the specified locations even when some may to be incorrect.
4. Click Continue with these bindings, and then ensure that you save the solution when you check in the project (on the File menu, click Save all).


The problems starts at #2. When you receive the "prompt" it's not a prompt, it's what we call a "dialog box" or perhaps a "modal dialog box". there's no option to save the solution and since it's modal, you can't save the solution in the explorer or the application menu.
I tried going straight to #3 (by unbinding and then binding). I received a dialog boxes saying that the projecty would not be tied to source control, but I went ahead anyway. The initial evidence that that didn't work was that all files still showed as checked out (I had no files checked out in VSS).
I then decided to go to #2 and save the solution. Nothing happened, so I tried to check in all files. I then recieved a series of dialog boxes, the last one said that I wasn't able to add to source control because the files were already in source control.


I tried to resolve the issue using the following method of my own devising, but as you will read, you're unfortunately going to have to delete the project and all related files and follow the instructions at the beginning of this post.

1. On the File menu, click Source Control, and then click Change Source Control.
2. When you recieve dialog box, click unbind, ignore alert box and hit ok.
3. click bind in dialog box and select the solution in source control.
4. click "OK"
5. go to the solution explorer right click on soltuion and select "save ...sln"
6. At the check out dialog box, select "save as..."
6a. I had to go to windows explorer and the properties of the .sln and unclick the "read only" checkbox.
7. save the solution (overwriting existing solution)
8. files still checked out
9. try to check files in
10. recieve a series of alert boxes, the last one says that you are not able to add to source control because the files were already in source control.

Here are some search strings to help this show up on google, etc.
the source control binding information has been removed for project localhost. The project will be opened without source control ASP
lost source control binding information .net

From http://www.developmentnow.com/g/55_2005_1_0_0_48312/Re_The_Source_control_binding_information_has_been_removed_for_project.htm

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