I have recently started to use Returnil Home Lux version 3.0.6517.4958-REL on WinXP Pro SP2. I was stunned today to find that the amount of free disk space on my hard drive had gone way down. I did a search for large files and found one: Returnil's RVSYSTEM.CCH, which was more than 25 GB. I went into the Returnil program to try to understand why this file was so large. I had told Returnil to drop all changes on computer shutdown, I had NOT told it to start with Windows, and I had shut down my computer several times since I had used Returnil. So why should that file still have been on my system? Oddly enough, though I made NO changes as I was poking around today, suddenly my disk space went way up and the RVSYSTEM.CCH file disappeared. But it was clearly there days after I had run Returnil. Why? Also, I don't understand what percentage of my free disk space I should allot to the Virtual System. I accepted the default, 50%, but I don't understand why it should be 50% rather than, say, 10% or any other percent. As it happens, the 25+ GB RVSYSTEM.CCH file was approximately 50% of my available free disk space, but do I need to allocate so large a percentage? What determines how much I need? I looked in the User's Manual, but I could find no explanation of why the default is 50% or what would happen if I set it to, say, 10%. I'd be most grateful if someone could explain this to me. Thanks in advance for your help.