Adam, you asked about leasing. It is a technical issue in Server Message Block (SMB) protocol v2 and v3. I will try to explain.
Windows uses SMB protocol part of the "File & Printer Sharing" option. Introduced in SMB v2.1, "leasing" relates to keeping file buffers open longer by deferring a remote disk "writeback" operation. In SMB v1, when you updated a buffer, you had to write it back as quickly as possible. With SMB v2+, you can defer the writeback, which means you now have a "dirty" disk buffer hanging around longer. The cause for this change is that for the file system's directory operations, you get greater efficiency for wild-card operations like COPY and DELETE. The effect is that enabling leasing of Access disk buffers will INCREASE the probability of corruption.
The mechanism of Access corruption most often (though not exclusively) is that you start to update stuff, and MSACCESS.EXE (the main Access code) in the memory of your local machine does the work and starts to write it back... but for reasons unknown, fails halfway through the process. So what you have then is a file that has an incompletely updated set of disk blocks. Since Access uses pointers heavily, if that update involves pointers that SHOULD have changed - but didn't - you now have an inconsistent database. Depending on exactly what was being updated, you might have problems with lost data or bad indexes. The Compact & Repair will not always be able to recover lost data since that might well have been what was supposed to be written back.
By turning off the "leasing" option for SMB v2, you make disk writebacks occur more often rather than deferring them - which doesn't close, but DOES shrink, the window of opportunity for corruption to occur.
Hope this explanation helps.