The discovered mailbox data is inconsistent with the actual data

I'm in the data store item Estimate Size show the size of the user and the user's actual size of the NSF file is too different, for example, the user's NSF file size is 3GB but here shown is 7.29MB I don't know if this is normal

At present, the NSF storage location of the user's Notes is "LotusDominodatamail" It seems to be the default path of the Notes mailbox store NSF, just because I saw the difference in data, I copied the NSF file under the default path of the tester to other places and gave sharing permissions, and executed the "locate data store.." After the operation is added, the value displayed by the data store item Estimate Size has not changed, is it a good thing for me to do this?  

Based on the error log file, it appears that the NSF files are not accessible or does not exist

What the problem is this?