I’m compiling a list of evil SharePoint errors: those errors that are so ambiguous and misleading that Google will shows 50 hits, with 10 different suggested solutions, and none of them work for your particular case.

Here is #1:

The URL ‘[url]’ is invalid. It may refer to a nonexistent file or folder, or refer to a valid file or folder that is not in the current Web. at Microsoft.SharePoint.Library.SPRequestInternalClass.PutFile(String bstrUrl, String bstrWebRelativeUrl, Object varFile, PutFileOpt PutFileOpt, String bstrCreatedBy, String bstrModifiedBy, Int32 iCreatedByID, Int32 iModifiedByID, Object varTimeCreated, Object varTimeLastModified, Object varProperties, String bstrCheckinComment, UInt32& pdwVirusCheckStatus, String& pVirusCheckMessage)
at Microsoft.SharePoint.Library.SPRequest.PutFile(String bstrUrl, String bstrWebRelativeUrl, Object varFile, PutFileOpt PutFileOpt, String bstrCreatedBy, String bstrModifiedBy, Int32 iCreatedByID, Int32 iModifiedByID, Object varTimeCreated, Object varTimeLastModified, Object varProperties, String bstrCheckinComment, UInt32& pdwVirusCheckStatus, String& pVirusCheckMessage)

I got this error when uploading documents to a document library. This error started to appear after I redeployed features to do with site columns and content types.

In my case the problem was a bad lookup site column definition that I deployed. This column was being included in 1 of the content types of the library, and hence becomes a column on the library, and hence caused the problem.

My site column (field) XML def looks like this:

<Field Type="Lookup" List="{8e980a24-9619-4969-9357-1eee9a1805c6}" ShowField="Title" DisplayName="Document Status" Required="FALSE" Group="All Documents" Description="Select the Archive option if this document is no longer Current and requires Archiving" ID="{cd94be8c-d754-4a6d-865d-7cb40375b11c}" SourceID="{36c01185-5d4b-4235-8f8b-59227bef7801}" StaticName="DocumentStatus" Name="DocumentStatus" WebId="{83255f8a-4772-4767-a261-376742747972}" Version="2">
	<Default>Current</Default>
</Field>

Notice the Default element. Because this is a lookup column, the Default value must have the format [id];#[value]. Changing the Default element to <Default>2;#Current</Default> fixes everything.

From my experience bad lookup column can lead to evil SharePoint errors. If you get desperate and nothing seems to work, I suggest remove all lookup columns from your content types and lists to isolate the problem.

Note: You can also get this error for completely different reasons. I have described the 2nd scenario here: https://bernado-nguyen-hoan.com/2011/04/18/sharepoint-evil-2-the-url-url-is-invalid-it-may-refer-to-a-nonexistent-file-or-folder-or-refer-to-a-valid-file-or-folder-that-is-not-in-the-current-web-the-2nd-scenario/