In about 50% of the cases I try to launch TrueCrypt 7.1 (portable) it causes Windows 8.1 Pro x64 RTM to get unresponsive to TrueCrypt. In fact the program hangs, and cannot be stopped either. Also in Taskmanager this cannot be done: it says that it is in use and therefor cannot be deleted/wiped from memory. I noticed that, although the rest of Windows and the open programs still work, the overall stability of Windows 8.1 is undermined, and to my idea this gets worse as the time passes by I continue using Windows. The only thing to solve this is to shut down Window 8.1 and to restart it. Only then TrueCrypt is removed from memory, and I can try all over again to launch it: this is so boring... Is there a solution to use TrueCrypt 7.1 in a proper way in Windows 8.1? The FAQ-section on the site of TrueCrypt doesn't say anything about a possible problem in using it on Windows 8.1.
I have not seen any issue with Truecrypt 7.1 on my Windows 8.1 Pro computer. I'm using it all the time since I have several Truecrypt containers I use every day. I have also used TrueCrypt to encrypt my whole OS disk. I'm also using Truecrypt on both my Server 2012 R2 servers daily, and no problems there either. Have you tried to remove and reinstall Truecrypt on your computer?
I don't think that would make any difference, as I have put the portable version of TrueCrypt on another drive, on which I can reach it in several Windows installations.
Ok, then the problem must be in another area... Maybe re-"installing" from withing Windows 8.1 might bring a solution; it's worth giving it a try.
I just thought of the fact that the problems might be caused by the the fact that on my computer TrueCrypt isn't installed, but only extracted and put as a portable program on another drive, as - as I assume - others have installed TrueCrypt.