Do you have activated the "Owner" or the "Permissions" column? In Active Directory environments Windows can take a long time to query these values. To speed this up, the only option is to turn off these columns using the"View" menu if not needed.
TreeSize is a stand-alone EXE and not able to do this out of the box. But our product ServerSentinel is specialized in observing servers for states like low disk space and send a notification by email or text message (SMS). Please find additional information at: ServerSentinel - diskspace sensor
You can compare a scan to another folder using "Scan > Compare with path". This will show the size and file count differences on folder level between the path that was scanned, and the one that was selected for comparison.
No. TreeSize does not actively change the archive bit, and the system only changes the archive bit if a file is written. TreeSize works strictly read-only when scanning and searching and also does not modify the last access date if possible,
When you are using the option "Use MAPI client" in the settings under "Export > Email", you need to make sure that an email program like i.e. Outlook is installed and operational.