In the Aug/28 update, for the first time I read suggestions about pacdiff and started using it very carefully; that’s when I discovered that I had a lot of .pacnew in both computers.
Also, I saw that the new shadow.pacnew only had one entry, with the risk of leaving me without access to the system; I think I mentioned it in that announcement:
After using * sudo pacdiff , I managed to find and get rid of all those old .pacnew files, then I reboot my system … cut …
I also found that some previous update, wreaked havoc on the shadow file; no wonder many people have complained that they cannot enter with their passwords, that new “/etc/shadow.pacnew” comes only with the “root” account:
I discard that shadow.pacnew.
I can certainly tell you that I checked the differences very carefully, and I did not see that my user will be missing from the groups during that update.
Also, and during the Sept/8 update my virtualbox was working correctly.
It was after the Sept/11* update that the problem started, so I deduce that this update removed my user from the group.
But, I think I found something strange in my PC at work, I found a file group.pacnew-
With a “dash” at the end, I don’t remember if I renamed it or if the Aug/28 or Sep/11 update left it as evidence of the update.
Although its date is prior to the Aug/28 update; and since the beginning of the year I have not had problems with the virtualbox in my work, the VM is a windows 10 that I use daily and even from home via RDP.
Addendum. So, the Sept/11 update didn’t give any warning that it would update the group file; so there’s a good chance it will happen again (hopefully not).
Where did you do this search in the logs?