error / null db tag

[RevitGary]

I recently have been getting this error. that crashes max

 

"mental ray has encountered a fatal error and the application will now shutdown. the error is: DB 0.3 fatal 041008: attempt to access null DB tag"

 

Anyone have any ideas on what this means. I get it when trying delete empty slots in a multi / sub object material. or when clicking on an existing multi / sub object material.

[padre.ayuso]

OK, this is an old thread, but after having looked for this solution and having forgotten about the solution twice, I want to put it in this forum so that I can find it in the future. The problem, which can still happen in Max 2010 is that either you have a submaterial material in a submaterial slot, this confuses the whole computer and in big scenes it will crash and MR can't handle this. Next, and the one I found to usually handle this is that one or many of your submaterials have wrong numbering. For example, a multiple material have the ID number 1, 2, 3, 6, 7, 8., etc., in other words, the sequence of its ID numbers are messed up. Hope this will solve any future issues with this error.