Microsoft has recently fixed a series of client crash issues in the Dynamics AX 2012 and Dynamics AX 2012 R2 clients. These were targeted fixes for symptoms such as personalization on forms that are set to pre-load and a series of WPF/GDI related errors which generally occurred on forms such as Sales Order entry with many additional fields added to the forms. The KB article for the hotfix has not been finalized yet, but if you want to obtain the hotfix before the KB article is finalized, log a support incident through your normal channels and ask for the hotfix related to KB article 2878051. Be sure to specify if you need the hotfix for AX 2012 R2 or the hotfix for AX 2012 RTM/Feature Pack 1.
If the new client/server executables in the hotfix do not resolve the issue and it continues, I would suggest opening a support request after capturing one or more crash dumps with a tool such as ProcDump or DebugDiag.
Kevin