[GNC] Huge number of missing transactions

[Daine Pearson]

Hi all,

I do see a few messages spread over the years about similar issues but 
most have gone unanswered so I thought I'd create a new one.

My partner and I have been jointly using GNUcash for a few years. The 
XML data files reside on a shared network drive.
I recently installed a new Win 10 computer and installed the latest (at 
the time) 4.11.
I did not think about the fact that her system was still running 3.6 - 
Probably the culprit...
Everything seems to have been going fine but yesterday she noticed all 
the payments into a credit card account were gone, leaving quite a large 
negative balance. I looked further and discovered this was true for many 
accounts but I do not believe any accounts were missing or completely empty.
I went into the shared directory and could easily see by the file size 
that a large data reduction recently occurred as the size suddenly drops 
from ~900KB to ~600KB.
There is also a 17MB (136325 lines) log file in that same time period.
Not so much had happened in the few days after that file size drop so I 
exported some new transactions that had been manually entered in the 
(corrupted) file and saved one of the earlier files as the new data file.
I updated both machines to the latest stable 4.13 build, imported those 
new transactions and just for kicks, ran the repair function which did 
not throw any messages so presumably nothing was fixed.
Things seem to be fine but it occurred to me that it would be useful if 
I understood better what the log files actually might reveal and if they 
also show actions taken by the program?
It seems pretty clear that each new transaction generates a log entry 
but I'm unsure how deletions, moved items, etc., are marked in the logs. 
I'm guessing the letters in the 'mod' column between Start & End mean 
something but not sure what.

I presume and hope that something about managing and saving the same 
data file under both versions is what caused the mishap but it would be 
good to understand the situation better so all thoughts welcome.

And presuming sharing files between different program version is a 
danger (which it likely is), I guess it would be helpful if opening an 
account file would trigger a cancel message if it was last saved by a 
different version, particularly a newer version.

Thanks... DP