Unattended setup error: "The path 'C:\..."' is not a valid non-root local path."

Hello,

Can anyone tell me what does this error mean? It arises every time I use a subfolder of the C:\EXCHANGE\DBLOGS\ folder as the LogFolderPath:

Looks as if the Setup did not see the first " character. If I omit the last subfolder (DB01) the installation starts correctly.

In other words, the path "C:\EXCHANGE\DBLOGS" works and the path "C:\EXCHANGE\DBLOGS\[ANY Subfolder]" does not.

???

Thank you in advance,
Michael