I got the following error with one solution.
Error 1 Error occurred in deployment step ‘Add Solution’: The solution cannot be deployed. Directory “SPCustomListFormDemo_Feature1” associated with feature ‘f0fb0300-f1a4-493b-ac43-68977d7d6e2d’ in the solution is used by feature ‘2d8b49b9-ba7c-4f7f-82f7-447e596ba96c’ installed in the farm. All features must have unique directories to avoid overwriting files.0 0 SPCustomListFormDemo
I used the following command to remove the feature with the ID “‘2d8b49b9-ba7c-4f7f-82f7-447e596ba96c’ ”
stsadm -o uninstallfeature -id 2d8b49b9-ba7c-4f7f-82f7-447e596ba96c -force
The next deploy from the Visual Studio 2010 worked.