Empty strings are not allowed

We migrated the developer environment from Sitecore 5 to Sitecore 6.0.2.

Basically everything went straight forward. Its not comfortable but ok. Some APIs have changed, that business as usual.

However – one problem took a while to be solved – the “Empty strings are not allowed - Parameter name: fieldName”.

We tried many different things to solve this – updating templates, verifying web.config, debugging and so on. Then we discovered – that one of our colleagues did not have the problem.

So I went to user manager, selected my profile, clicked on “Reset Settings” logged in again – and there – it worked.

In the meantime I learned from Sitecore Support that there is even a tool to fix the problem – you just need to open a case,….