Yeah, this is an extremely stupid bug Microsoft has. Here's the solution:
1. Go into any folder windows. Tools-->Folder Options-->View-->Make sure "Use Sharing Wizard" is checked.
2. Make a test file to share (Name it share.txt or something). Right click-->Properties-->Security-->Edit-->Press "Add"--> In the box that says "Enter the Object names to select", type in "Guest" (No quotes)--> Press "Check Names"-->OK-->OK everything
3. Now go into Resco's File Explorer and try again.
If that doesn't work, continue with these steps:
4. Download this and install:
https://www.microsoft.com/downloads/...displaylang=en.
5. Start-->All Programs-->Windows Resource Kit Tools-->Command Shell
6. Enter the following commands one by one:
net user guest /active:yes
ntrights +r SeNetworkLogonRight -u Guest
ntrights -r SeDenyNetworkLogonRight -u Guest
7. Now try again.
Good Luck!
~John