There are several applications known, which causes the crashing/hanging on the file dialogs:
1. Adobe Drive (part of Adobe CS3 & CS4)
2. Symantec Endpoint Protection
3. TortoiseSVN
4. MediaPortal / Dokan Library Bundle
5. Cryptomator (WinFsp component)
They install drivers/thunks into Windows, which causes EAC to hang. Please check the internet for possible solutions for any of the given applications (if a deinstall is not feasible).