I have a difficult question and I really hope you could help me with it. To make things easier, I will structure my question as points as follows:
This is a SharePoint 2010 Intranet environment.
There's a SubSite that has its own permissions (Unique permissions), let's call it (SubSite1).
There's a custom web part that is added on the aforementioned SubSite (SubSite1), and this custom web part works perfectly fine.
There's user e.g. (Germany\User1) that has Full Control on the aforementioned SubSite (SubSite1). However, Whenever the user (Germany\User1) tries to edit that custom web part => He gets: "Access Denied" error !
The user is using the same account (Germany\User1) to access the Windows, his machine, and SharePoint site. So, The user has no other account.
I already followed and checked everything on this article: (http://support.microsoft.com/kb/2001366?wa=wsignin1.0), But unfortunately it didn't help.
Also, I checked with other users e.g. (Germany\User6), (Germany\User444), (Germany\User99),...etc which all have EXACTLY the same Full Control permissions level, Yet...All these other users are able to edit the web part normally without any issues at all. Which somehwat means: The custom web part doesn't have any actual error.
I don't know Why this user (Germany\User1) is the ONLY user who is getting the "Access Denied" error even though his account has Full Permissions level and all his colleagues with the same privilege are able to edit the web part normally.
What do you think? Could you please help me out to investigate and resolve this peculiar issue ?
Thanks, and I would greatly appreciate your inputs !