Hello everyone,

 Im only getting this error while upgrading to the latest version (7.3.4) originally Im at version 4.9:

[ERROR] DotNetNuke.Services.Upgrade.Upgrade - System.NullReferenceException: Object reference not set to an instance of an object.

 

tracing in the source code (lines of code where error happens called from  first to last):

FolderManager.Instance.Synchronize(portal.PortalID, "Templates/", false, true);
-> var mergedTree = GetMergedTree(portalId, relativePath, isRecursive); //this is inside method synchronize
-> ClearFolderProviderCachedLists(portalId);//this is inside method GetMergedTree
-> var folderProvider = FolderProvider.Instance(folderMapping.FolderProviderType);//this is inside method ClearFolderProviderCachedLists

My problem is that the FolderProvider.Instance(folderMapping.FolderProviderType) is null for all my portals. (all my portals throw the same error)

everything before, and after this error in the installation is successful.

Any pointers/hint/things to try are welcome.

 

thanks in advance.

 

ok, so apparently during the upgrade the web config is modified and the folder providers are added, but they are added after the data dictionary is made.
so adding this to the web.config before the upgrade solved the issue:

<section name="folder" requirePermission="false" type="DotNetNuke.Framework.Providers.ProviderConfigurationHandler, DotNetNuke" />

<folder defaultProvider="StandardFolderProvider">

      <providers>

        <clear />

        <add name="StandardFolderProvider" type="DotNetNuke.Services.FileSystem.StandardFolderProvider, DotNetNuke" />

        <add name="SecureFolderProvider" type="DotNetNuke.Services.FileSystem.SecureFolderProvider, DotNetNuke" />

        <add name="DatabaseFolderProvider" type="DotNetNuke.Services.FileSystem.DatabaseFolderProvider, DotNetNuke" />

      </providers>

    </folder>