In 4D v18 the location of the logs related to maintenance (compact, repair, verify) have been changed.
As such the following call will not properly return the desired location:

Get 4D folder(Logs folder)

Instead the are two ways to get the location of the maintenance logs.
To get the location use selector 11 with the command which will return the logs location

Get 4D folder(11)

Alternatively, to get the direct path to one of the maintenance files, the new File command can be used passing the constant for the specific file.

• Compacting log file (6)
• Repair log file (7)
• Verification log file (5)

The command will automaticly return the most recent version of the log found.
For example to get the latest verification log call:

File(Verification log file)

Related Asset:
4D v18 MSC Log File location