If you didn't read the puzzler from Friday, here it is.
Answer:When Target Designer is launched, its Filter Manager checks the 'filter' folder at ".\Program Files\ Windows Embedded\ filters" for any filters you may have previously created. These filters are loaded early on so they'll be available whenever you're ready to work with a configuration.
In this MVP's case, one of the filters was corrupt. Not your everyday corrupt mind you, but pretty close to not being corrupt. Remember in this scenario TD was hanging. If this was your everyday run of the mill corrupt filter file TD will show something like below instead of hanging:
If you'd like to see it in action here's a test, with TD closed use notepad to create an empty text file called 'test.flt' and save it to the Embedded 'filters' subfolder listed above. Now launch TD and try to open an existing SLX or try to create a new blank configuration. It'll error with some helpful information that your new filter file is corrupt and TD doesn't like it, click the thumbnail above to see the error. Pretty simple, right?
But in this MVP's case, the filter file was unique in that it had caused TD to hang. After deleting the filters in that folder all was well with the world again and he was able to get back to work with no loss to the configuration or the database, just the leftover filters had been removed. I just wish I had asked him to send me the filters so I could add it the bug report, more than likely it had become corrupt in the cmi stream as it was being saved to disk. <sigh>