I'm just going to contribute this here. I had an existing SQL DB, used to be Mertech, now MSSQLDRV. Took a while but got all the INT files right finally and the driver prefixes set finally but I had one file I could see in DBBuilder but not in DBExplorer. Would crash Explorer. If I brought it up inside the development system, I got this 4262 Error, same error, everything. The error does tell you what's wrong, would have saved some time if I had read the details a little closer. It said all my indexes were fine but 0 and listed them. These are all very old recnum files. The INT file was fine, turned out that INDEX00 on the SQL Server was missing altogether. No idea why, I restored from a SQL backup. Anyway, recreated the INDEX00 Non clustered index in MS SQL Server Management Studio and it's very happy now. So I'm just saying you might get a 4262 if there's an index missing or out of whack on the actual SQL Server itself.