Attila was talking about the temporary error message displayed by updater.bat.
I could finally understand it with your writing.
This is an error message with no adverse effect.
Windows can not rewrite running exe file.
Therefore, when updating program, FEBuilderGBA entrusts processing to a batch file named update.bat, and FEBuilderGBA exits.
After taking over the process, update.bat overwrites the data of FEBuilderGBA.
The problem is that at the moment FEBuilderGBA launches update.bat, FEBuilderGBA is still running.
This is, of course, because FEBuilderGBA starts update.bat.
That time is less than 1 second.
It is a moment for human beings, but it is quite a long time for machines.
Therefore, update.bat checks whether the process of FEBuilderGBA has ended before writing to the file for updating.
If FEBuilderGBA is running, wait for a while and check again.
If it can be determined that FEBuilderGBA has finished completely, update the file.
The problem Attila is talking about is probably an error that is displayed at the time of confirmation.
This is not a problem.
However, since it looks bad, I will fix it so that the error message will not appear on the screen later.