Change to Drive Letter

To change to a specific drive letter while the command prompt directory is using a different drive letter than the one you need to change to, simply use the /D parameter with the CD command (e.g. CD /D <DriveLetter>:) to change to a different drive letter before running proceeding commands.

Delims

You should omit using the delims=" in the FOR loop as that tells it that space is not a delimiter which is not what you want to prevent that cr/cr/lf issue as per the LotPings comment.

• FOR /?

    delims=xxx      - specifies a delimiter set.  This replaces the
                      default delimiter set of space and tab.

Since it states the default delimiter set of space and tab when you put delims=" just like that with the ending double quote after the equal sign =", that tells it there are no delimiters now.

Compact

Since Compact runs against files in the directory without specifying the path in an argument, if applicable, you can first CD /D <Letter>: and then run Compact /C to compact all files in a directory, or Compact /C /S to compact all files and folders recursively in the directory.

Batch Script

for /f "skip=1" %%x in ('wmic logicaldisk get caption') do (
    CD /D %%x
    Compact /C /S
    <Next or other command>
    )

Note: The drive letter is listed in a <letter>: format e.g. H:. So CD /D H: works just fine. You will obviously add the \ to the end of the iterated %%x i.e. %%x\ if you need to append a path to use a full path (%%x\folder\path) as a command argument e.g. dir %%x\folder\path.

Further Resources

• CD

 Key
   /D : change the current DRIVE in addition to changing folder.

• Compact

Key    
   /C        Compress the specified files.  Directories will be marked
             so that files added afterward will be compressed.

   /S        Perform the specified operation on files in the given
             directory and all subdirectories.  
             Default "dir" is the current directory.