We've discovered a bug in the backward compatibility of ROOT, which we hope can be fixed ASAP.

Simply opening the attached root file (root workspace [workspace.root.zip](https://github.com/root-project/root/files/6334250/workspace.root.zip) .root or otherwise) works fine in 6.22.00 but fails in 6.22.06 and master. ROOT Crashes which is definitely a bug, right?

I've traced the problem to

... the problem is that old->GetValueClass() ends up being a nullptr.

Something was introduced into 6.22 branch and master branch in the past 12 months that makes this null. I am hoping a developer working on this area of the project will have an idea what's happened here!

Thanks!
Will