Jochen,
Common mistake to specify drive on destination.
quote:

C:\>ren /?
Renames a file or files.

RENAME [drive:][path]filename1 filename2.
REN [drive:][path]filename1 filename2.

Note that you cannot specify a new drive or path for your destination file.

C:\>

So, should be:

code:

shell '%comspec% /c ren "h:\exchange" "outlook"'
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