How to Fix: "Failed to open serialization file readonly file system"

Hi, I performed apt update +upgrade and rebooted the machine when prompted to do so. Now my droplet fails to boot and gives a message of “Failed to open serialization file readonly file system” Is there any guidance on how to resolve this issue?

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Accepted Answer

Ok so after running up a new droplet with my week old backup and updating to the point that it broke as described. I identified that it was the snapd package (snapd/bionic-updates 2.42.1+18.04 amd64 [upgradable from: 2.40+18.04]) that caused the break.

I then booted via the recovery console and removed the snapd package. I then shutdown and switched back to booting via the standard method and the test system is now working as expected.

I am now going to fully update the test system and reboot.

If this works I will replicate this to my live system.

Edit: This has worked and I have replicated to live system and all is working. The ‘snapd’ package was the issue for me, once removed all was good.

Uninstalling snap solved my problem as well. I’m going to upgrade to a newer version of Ubuntu to see if this problem persists there.

Great thread! I just found my way here after discovering snapd caused my 18.04 ubuntu server to go into read-only mode after a reboot.

I was using snapd to install certbot, but I found a tutorial with installation without snapd. See: