Hello,
The two ways I know how to do this is to clean up AD on your end and then do a scanning update on your LS instance to scan the Users OU. Alternatively, in Configuration > Scanning Setup > Server Options, you can set options to remove users not found in AD under the "User and Group Cleanup Options". Keep in mind, if you have assets actively assigned to users in Lansweeper that point to those AD records, you will lose that information once the AD record is cleared.
Alternatively, and beyond my scope, you could clear the tables/records from the database itself but it's not recommended in case something gets messed up.
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Union Home Mortgage's "Lansweeper Guy"
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