I had an application crash which took down all my other apps which were connected to the internet. When I got everything back up I noticed some TWS behaviors which sounded familiar from other ET threads. The TWS launch was slow. When it came up there were no quotes, but the order line was there and it seemed ready to accept an order. The P&L data in the account window was an impossible value (for ES). Another time TWS was a blank, gray window. The socket connection to IB was giving me a lot of problems (took a long time to get established and seemed to hang regularly). Relaunching, rebooting didn't help and the system was previously working normally. I suspected some file corruption. I noticed that only some of my personalizations were present (file not being read maybe) and I remembered something about a file corruption issue with TWS. Solution: Deleted the XML folder which is named something like D:\Jts\dwlcjwfzv Once you delete it, TWS will recreate it the next time it is launched. When I restarted TWS, it was working normally. Of course doing this means you will lose all personalizations, pages and hotkeys. Luckily I made a copy of the \JTS directory. I copied over some of the files which seemed important: hotkey.lyt, layout.lyt, pagesettings.lyt and toolbar.lyt. If you have not saved a previous, good \JTS directory, you can still try this. Once you've deleted the XML directory, go to an old copy of it (the exact same one you deleted) and copy the critical files from the bad XML directory to the newly created directory (one at a time) until you find the one that makes TWS go weird. Relaunch TWS, each time you add a new file and see how it works. The file that makes TWS go bad is the only one you can't recopy and you have to manually recreate the work associated with that file. You can copy the others and save some of your work.