Why does Enterprise Manager return 'Invalid cursor state'?

When trying to rename a column, change its data type, or alter other properties such as default values or formulas, you might see the following dialog: 
 
 
 
The first course of action would be to stop making DML changes with the GUI. Use ALTER TABLE statements from a tool like Query Analyzer. (In addition to being immune from this problem, you have other advantages such as being able to save your script in source control. See Article #2455 for a more in-depth comparison of the pros and cons of each tool.) 
 
If you really want to use Enterprise Manager, there are some steps you can take to overcome this problem. 
 
Make sure that if you are connecting to a server remotely, both the server and client version have been updated to the same version of SQL Server and the same version of MDAC. The error could be caused by a mismatch of one or both of those components. (For the most recent version of MDAC, see MDAC Download Page). 
 
Make sure that the target database is an appropriate version (and is in the correct compatibility mode). The problem might exist because a SQL Server 2000 Enterprise Manager thinks it can apply specific ALTER commands to a 6.5 server, or a 2000 database in 6.5 compatibility mode, for example. To check the version and/or compatibility mode: 
 

USE MASTER  GO  SELECT @@VERSION  EXEC sp_dbcmptlevel '<database_name>'

 
(For more information on checking the version of SQL Server and the status of any installed hotfixes, see Article #2160.) 
 
Ensure that clients on Win9x platforms are using SQL Server authentication, not Windows authentication. (See KB #243292 for more information.) If you can avoid managing SQL Server from Win9x clients altogether, that's the path I would recommend. 
 
This error can come from applying a post-SP3 hotfix, such as 859 (from KB #821334). Your first inclination might be to remove the hotfix and start over, but of course this is not necessarily going to be acceptable in many scenarios. My suggestion is to use Query Analyzer, rather than Enterprise Manager, for schema and/or data manipulation operations. (See Article #2455 for a more thorough analysis of the pros and cons of each tool.) 
 
Finally, if you can get a hold of a hotfix 876 or greater (e.g. 878, from KB #838166), it's been implied from 3rd parties and individuals that this problem goes away in later builds. Hopefully, Service Pack 4 is not too far away.