I fixed this issue by editing the registry under these two locations:
Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Cakewalk Music Software
Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Cakewalk Music Software\Cakewalk\Core\ContentLocations
They had the old D:\ drive paths from when I initially installed the software. I changed them to C:\ and it solved the issue. e.g. C:\Cakewalk Content