Today, I had similar problem to that of Peti1212 with being denied access to data on C drive and showing it with 0 Bytes, on two laptops. I think MS has a serious bug in the Homegroup feature. I joined the Homegroup from Win 7 on a toshiba laptop trying to make my C drive and Printer accessible to another Sony Laptop ( which by the way created the homegroup at installation). First the Sony lost all acess to C drive data and was denied permission to change any properties of the security features on that drive. Later the Toshiba fell into the same malaise, but fortunately I was able to change ownership via the security tag on the C properties menu. The files on C reappeared. The Sony is still unable to get access to any thing on the C drive except documents. Strange error messages appear saying the administrator has been blocked or the file names are incorrect or simply access denied. Help badly needed and appreciated. I do not want to rebuild the system

Hi, It's a known bug. Please try to take following steps to check if it works:1. Login in safe mode with command prompt2. In command prompt type - NET User Administrator /active:yes3. Start computer in normal mode and there should be an administrator account and yours, log in as the admin.4. Log out and then log in with your account.5. Go to control panel, administrative tools, computer management, disk management, right click on c drive and go properties. Go to the security tab and click advanced. Go to permissions tab, Change Permissions. Highlight your account and click edit, make sure all allow boxes are tickedAlso, hope following thread can help you: Cannot Access C Drive After Deleting HomeGroup on Win7 RCThanks.

Thanks for the response. I followed Gianello's solution via changes to the registry and a few other Tweaks to unlock files. This worked but I'm not sure yet it is a correct solution. Regardless, If I have any future issues I'll try your solution, as it seems more straight forward. Thomas

Thank you Thomas.I will mark my reply as answer. If similar issue was encountered again, please unmark it. Thanks.

Thank you for the inputs, Robinson, I have the same situation but this does not resolve my issue. I am still unable to take ownership of theCdrive.

Even though this created an admin account, the admin still has no privileges. Well windows says it does, as does my log in, in the user area. But access to C is still locked and I can't gain access to any sharing or security options still as it says that neither account has access... Not solved...

Just found this... http://support.microsoft.com/default.aspx/kb/972407