As I mentioned in a recent post, our test department submitted a defect to us regarding the XML Serializer when running under a Japanese username.

We were able to replicate using a small test application which isolated the call to the XML serializer only, but then we had to isolate the environment which led to this problem.  It worked fine under English usernames, and fine under OTHER systems which used a Japanese username, so after trying a few permutations and eliminating unneccessary steps, we reduced it to the following:

1. Install Windows Vista (we used Ultimate edition)
2. Change System Locale to Japanese
3. Create User using japanese characters
4. Change System Locale to anything other than Japanese
5. Run Test Program - exception

What was curious about this was if we omit Step 2 then we do not get the exception, and if we include Step 2 but omit Step 4 then we also do not get the exception.

We should be hearing from Microsoft soon about this, and I'll post the results here when they are received.  Because of the nature of reproducing this exception is so contrived, I'd be surprised if we can do anything about it.