Issue: Fatal Error: attempted to instantiate non-existent class vw_Dependency_Model

The ZIP contains this file and I do not receive this error on any of my XenForo sites that were uploaded.

- You either did not upload vault/core/model/dependency/vw.php at all or part of it is missing (try uploading it again)
- Or your PHP instance cached the file while it was being uploaded, rather than after it was uploaded. This is a known bug in PHP's Zend Opcache. Try restarting the PHP process.

Either way this is not a bug in VaultWiki as there is nothing we can do on our end about either situation.

Did you check with IIS instead of apache? That was a common cause for errors on our site regarding VaultWiki. The file is present and is uploaded completely (header and footer are there). I already restarted the entire IIS, but to no avail.

You were able to run the upgrade script without problems? This error appears only on the forums / not in the AdminCP?
Do you use different subdomains for forum, AdminCP, or wiki?
Do any of your subdomains go through symlinks on your file system?

If you use subdomains and/or use symlinks, then you may need vw_config.php files in some, if not all, of the affected directories. You can find this file in the do_not_upload folder of the ZIP, in one of the "subdomain" sections. For each copy of this file you upload, edit the file to specify the canonical server paths for the forums and VaultWiki. I'm not sure why you would suddenly need these files after upgrading, unless you had them before and removed them / overwrote them by mistake when you were uploading.

Nope, as soon as I uploaded VaultWiki and enabled it in the AdminCP, the whole page was unavailable (even the frontend). I then had to disable the listeners via config and disable VaultWiki.

I do not use different subdomains and I ain't got no symlinks.

It sounds like VaultWiki is unable to automatically detect the path to itself, so defining the path manually should help.

In your vault/config.php file, find the following line:
And adjust as appropriate.

https://gyazo.com/7e261ad4dfb1a578968d70f57e4bd9b2
That is the error message without the path.

With the path specified, it just yields a 500 HTTP:

Please check the owner and file permissions on the vault/model/dependency/ directory and contents. You can also get this error if PHP does not have permission to reach the file in question.

Do you have an open_basedir restriction in effect? I'm not sure what the correct path should be in IIS with open_basedir. If you have that setup, please submit a ticket so that we can find a solution that works on your server: https://www.vaultwiki.org/members/?do=tickets

Alright, is there a list for the appropriate permissions?

It varies by server. I don't know what users are on your server and you should not post them. The directory needs to be executable by whatever user PHP runs as and the file needs to be readable by that user. This can easily get messed up if you upload files via FTP using a different account than PHP's user. After uploading, it's a good idea to chown the directories you just changed.

I just realized, that, when I re-downloaded VaultWiki (the full version), the folder was not present:
https://gyazo.com/ccf65c3e45ca3d0f9bb7c6eeac67960f

Sorry, I misspoke. The correct location is vault/core/model/dependency as specified in the error message. Make sure this location has the correct permissions.

This directory is readable by the IIS PHP user. I'll go ahead and create a ticket, then.

Thank you for filing the ticket. Some new security measures we had added for 4.0.20 were too strict for IIS environments. I've made some changes to that protection and the non-existent class error has gone away. You should be able to complete the upgrade process now.

Marking this as Fixed in build 002.