I have an instance of SSMS 2008, for which the option to edit data in a table doesn't work. If I right-click on any table in the Object Explorer and select 'Edit top 200 rows' I get an error dialog 'Invalid prefix or suffix characters. (MS Visual Database Tools)'. The error seems to be associated specifically with SSMS, not with SQL Server (because this SSMS instance gives the same error no matter what database I connect to, but I've verified I can connect to some of the same databases using SSMS on other machines without the error). (However, our firewall prevents me using SSMS on other machines for some crucial tasks, so I do need to fix the problem).

Googling for the error suggests that I should change the prefix, suffix or escape character, but without any indication of how you can make that change in SSMS. I'd also note that I'm not aware of having done any customization on SSMS since installing it, so would be surprised at having to make such a change now.

Does anyone have any idea what the error message means or what I can do about it? Or how I can change the prefix/suffix/escape characters if that is really the problem.