Failed to load Project file - NOT fixed by PnPLocalDataCachePurger.exe

[Jroper]

We are having a serious issue with a lot of drawings where the project.xml is not open.  They are mostly the failed to load error with some variation

Failed to load Project file

\<path>.\Project.xml

or

Failed to load project

<path> Project.xml

PnPCompletionStatus.FailedToOpenDatabase

Login failed for user ".

We suddenly had a rash of this happening at the start of this month.  It is NOT fixed by purging the local data cache.  We considering every variable in our network, win updates, any sql updates.  It doesn't seem to matter who opens these projects or on what machine.  It's localized to our main office network so it doesn't seem like a WAN problem.  It is intermittent. 

Can someone throw out some ideas that are not related to any super-technical network or windows issue because we have had every IT Admin look at every angle of this problem with no results.  What in the Project.xml could be causing the whole project not to open?  When you click on the Project.xml what going on under the hood?  When we examine projects that are having a problem, we notice that the <ProjectPart name=lines in the .xml files look a bit weird.  Most good projects have PnId, Piping, Iso, Ortho .xmls.  The basket case projects only have 1 or 2 .xml entries and the name and file name are sometimes different. 

[KenFauver]

A couple questions for you:

1. Are you using SQL Server or the out-of-box SQLite file?
2. If using the out-of-box SQLite file, how many Plant Users are on the project?

[Jroper]

The six projects we looked at, 4 were SQL Server, 2 Lite. We don't have more than 2 people on any of these projects at this time so SQL traffic is pretty light.

Here are some more symptoms.  What would cause a brand newly formed project to give these errors right after creation when trying to open the project?

'<path>\IsoPart.xml

<path>\MiscPart.xml

'is read only

[jabowabo]

I would try logging in to a pc with domain admin credentials. If it works then it is a permissions problem.

[Jroper]

Thanks for the reply.  We have tried that we found no evidence of a permissions problem.