oddi,
Use the same 7z cmd line settings as you used previously.
The 'Default' setting with modern 7z.exe will create LZMA2 archives, LZMA2
can not be processed by t7z..
Setting t7z.exe directly in CMP's settings is just crazy.
So post processing t7z.exe with after CMP "Scanning & Fixing" is unavoidable.
Hence the reason I set
-mx0Plus the way CMP works 'as current' by adding 'file by file' on a Rebuilder run, so using higher 7z compression is a waste of time & resources..
I would never suggest anyone try Rebuild to 7z (a whole set)
This is why I call my 7z cmd settings 'Maintenance Settings" for using CMP with an already 7z & merged set.
Someone wishing to convert a MAME split & zip set to merged 7z, should use ZIP and "Scanner" to merge & Fix FIRST.
Then send the 'ROM Root' to t7z.exe (or Drag, Drop folder onto t7z.exe) to convert to t7z..
After complete, then configure CMP to work with 7z.
(I will re-t7z the 'ROM Root'
occasionally, definitely
not with every dat update)
Maybe if Roman makes some core changes 'one day', well that advice might change

Roman,
Monday I will continue to test everything I can think of - starting over again with today's build.
Thanks for the effort you have put in, it's really appreciated.
I know I have worked with you fine-tuning CMP to be the best it can be, and you haven't rejected anything.
The new CMP opens up 7z usage, on a 32bit OS which couldn't be achieved previous to the latest updates.
Champion you are !
Starshadow,
+1 for your effort on checking the >4Gb 7z, both 32 & 64