Some Mac users have the same problem that they cannot open their files after finishing Mavericks installing. Some said that if they type the file's name in the search bar, it works well. Some said that they can browse the files as usual if they go to the hard drive but if they select the desktop, downloads or home folder from Finder in sidebar, they are grayed out.
Well, this might be corrupted Finder preferences. You can fix the problem in this way:
1. In the Finder menu, click on the Go > Go to Folder option
2. The Go to Folder tab pops up like this:
3. Copy and paste or type the text /Library/Preferences/com.apple.finder.plist in to the blank field, and then click Go button
4. Move the com.appl.finder.plist file to the Trash
5. Restart your Mac
You should be able to open your file from the Finder now. Have a try.
If not working, according to some Mac users who have the same problem, you can try this: in Finder, highlight the folder that is gray out and use command + J to change the view settings.
Another way that provided by some of the Mac users sharing the same problem on reaching their files after upgrading to Mavericks is: go to the Users & Groups, change to old user and then everything will come back.
That's all we can provide with you. Please inform us if you get more methods. Thanks in advance for offering us and the Mac users useful information.