Description of the need While working on https://github.com/backdrop/backdrop-issues/issues/3979 I realized that the updater throws exceptions at an early stage of the process, when there's nothing broken (yet).
This might be confusing for admins, especially Backdrop novices, because an exception usually means, something's broken really badly. And that's not the case at that early stage of updating (files got downloaded and extracted, the install itself is untouched).

Doesn't this look like this Backdrop install is broken? It isn't.
Proposed solution If nothing's actually broken, it might be better to abort the update and show a helpful message. Log detailed information, possibly with links to documentation. We also need to consider that updating happens in batches. The fact that one project fails, doesn't mean all of them fail. (But that needs some more recherche...)
Alternatives that have been considered Sticking with UpdaterExeptions.
Recent comments
well @herb I cannot believe it, but the webform module was there in modules on the disc, but missing in the listed modules, so I delete the module folder, and downloaded it again. Then...
My Webform Worksheets have disappeared
The only thing I can think of is to make sure Webform module is enabled and that the content type that needs to contain the webforms has Webform enabled for it. Edit the content type and make...
My Webform Worksheets have disappeared
@yorkshirepudding, In the end I fixed it by deleting the config/active folder contents, copying the config/staging/ files into config/active, importing the database again and clearing the caches...
Importing the staged config throws an error: another field with the same name already exists