I just booted the latest XFCE and Cinnamon ISOs to run the Memory Test. It still shows up as an option in the Grub menu, but when you select Memory Test it says, “error: file ‘/boot/Memory’ not found”.
Is this a packaging error and should Memory Test be on the ISOs or should the option be removed from the Grub menu?
Yes, I found the same issue on Manjaro i3 ISO (21.0.2 at the moment). The good fellas at Manjaro’s need to fix this one in the next releases. Memtest is still there but the grub’s menu is unable to invoke it because the variable inside it ($1) becomes “Memory” instead of “memtest”.
In the meantime you can easily use memtest by selecting “Memory Test” and pressing letter e (Edit). Then, change the second line from linux16 /boot/$1 to linux16 /boot/memtest and press Ctrl-x to boot.
It turned out that this issue was caused by something else for me. The open source memtest+ program is an old 16bit application. It will not run on a UEFI-only booting system. There is some more information here.
I needed to enable legacy bootmode in the BIOS/UEFI in order to run memtest+. When I boot in UEFI-only mode, I simply do not see the memtest+ option in the Grub menu at all.