It happens like this:
Once you install QV desktop personal edition in a computer, QV assigns a key to it internally. Once you create a qvw file that key gets embedded in the qvw file. Now this qvw file can be opened from your system (since that has the same key) and systems that has a valid license. When you try to open a file created by somebody else, it would find a mismatch in the key and warn you - if you open that file your system key gets changed to that of qvw (from somebody else). Now if you wish to open qvws that were created by you - qv finds that they are having different key, so it warns you (even if it was created by you). If you open the file forcefully your system gets back the key and then be able to open all the qvws were created by you earlier. But note here, in this process you have lost two chances of recovery (read -'key change') out of maximum four chances.
That means, if your fourth chance gets a foreign qv key (from other user-created qvw) you would not be able to open your own files anymore. Hope this helps.
