I'm not aware of any issues specific to MS-Access on virtual machines.
Can you provide more information about the issues and explain how the behaviour differs between physical an virtual systems. Please also provide any application specific information (architecture, etc), and a brief overview of your virtual infrastructure.
My basic structure is, I'm trying to deploy virtual server with VMware ESXi, my client is already using a server with VMware ESXi 5 as a test basis, however it uses an application developed in MS-VB with database MDB.
In real physical structure, the application runs without any problem, I came to settle in the worst machine I own and ran correctly, but in the virtual structure, the application gets to open but when it starts to manipulate the data to the application, is very slow, the physical structure does not realize slowness, and virtual arrives to take 3 minutes to answer the application.
Thank you for your interest.