OpenMsgStore fails: MAPI_E_NO_SUPPORT or E_ACCESSDENIED

I have to support an old C++ program (I am not its author) that uses Extended MAPI to scan mail folders from Outlook 2007. Suddenly the software began meeting problems on one customer's computer by the following scenario: call of OpenMsgStore fails for some folders with code 0x80040102 (MAPI_E_NO_SUPPORT ). for other folders it fails with code 0x80070005 (E_ACCESSDENIED). But other folders opened by OpenMsgStore OK.

What can be reason of the problem?