critical error on all of my VMs

[FartOnHeart]

Unfortunately, all my VMs are giving same error. My bad day started when a windows guest vm was not giving me enough resolution and exe generation process transferred same infection into exe too. generated exe file was not showing scrollbars correctly. I tried my best to get rid of resolution problem but nothing worked. I had to deploy the exe so to my bad luck idea of using qemu with virt-manager came to my mind. I installed gemu and created new win10 guest VM. It worked well except for shared folders were not properly setup.

Because of shared folders issue another stupid idea came to my mind. I thought i could attach vmdk instead of creating new one. I tried to attach one of my important win8 guest vmdk to virt-manager. it did not work. and guess what i had no backup. damn .

After that i decided to get rid of qemu and again tried to fix the resolution problem.
That was the time when i came to know that my win8 guest Vm which i created with virtualbox is not running in virtualbox any more. And when i checked other VMs(all created with virtualbox) were giving same "A critical error" message.

removing and installing Virtualbox did not solve problem. Now i have no VM that can be attached to virtualbox including those i did not even touch. I think its problem with virtualbox setup because those VMs i never touched are giving same critical error.

This kind of frustrating situation on week end gonna destroy my happiness for the week starting from monday.
Please help me.

The VM settings were not changed and all VMs with given limit of disk and ram were working fine before the "A Critical Error". I have bunch of VMs including Windows and Linux. none of them are working now on my debian 11 host.

[scottgus1]

Your Linux host has classic Qemu-itis. Qemu and/or KVM is still enabled on the Linux host OS. Qemu interferes with Virtualbox.

Web-search how to turn Qemu back off and your Virtualbox should return to normal operation. Though after all that thrashing it might not.

And if/once you get Virtualbox running again, if this:

a windows guest vm was not giving me enough resolution

means a VM was not expanding to full screen or was stuck on old-school 1990's screen sizes, please start a new topic, it could be a Guest Additions issue.

[FartOnHeart]

Hi, scottgus1,
Your answer was 100% exactly the reason and after removing virt-manager (not the qemu because qemu was removed already). everything returned back to original position. No more Critical error and all VMs are back online. This is wonderful thing made my day great. Thanks a lot for help. have a wonderful day.

[scottgus1]

You too! Glad you're up and running.