I mean both Windows and SQL Server. It's possible that a patch was applied to one machine that was not applied to the other and it is causing the issue. You need to make sure that both Windows servers and both intances of SQL Server are running the exact same versions of everything. I've seen times where one server was running automatic updates, another was not, and it caused issues.

>DO you mean the sql servers ?
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>I've updated this thread since as I found that passing an empty string to the clr was causing the problem on the 2008 server box but was not a problem on the XP box.
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>>And both are patched to same service pack and hot patches?
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>>>Hi Craig
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>>>Both are SQL Server 2008 R2
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>>>the development box is XP professional. The server is Windows Server 2008 R2