Note: My application uses about 80 % of the available system memory, which is all right because it’s the only application running.

Does QProcess consume a lot of memory?

can you try using the full path to reboot or shutdown?

I think I know what’s the problem:
The fork that must be somewhere inside QProcess can’t work, because there isn’t enough memory left to fork the current application. Why I wouldn’t get an error state I don’t know.

I have solved this by having a worker script run in an endless loop that will execute any shell script following a specific naming convention. I create a script containing the reboot command, and let it execute.

have you tried to add “0” to your shell command ? “shutdown -r 0”.

if it does not work, may be the problem cause that you are not the root.

I am root. And it used to work, before I expanded the buffers to use most of the available memory for archiving.

Suppose your command is in /usr/sbin/reboot you can try with:

My first try was based on startDetached. It seems to do a fork internally, too.

Have you tried with the full path of reboot command?

No. Plain Reboot used to work just fine. Colleagues with 20+ years of Unix experience assured me this is an underlying OS limitation.