Shared mailbox – users cannot create or view subfolders

Okay, sorry to dismiss the earlier Server Fault message--it led me on the right track, at least. I called Dell support and had them walk me through disabling the performance features on the NIC, which resolved the issue. I think the key was disabling global chimney and receive side scaling, as I had tried most of the other steps as per the other Server Fault question posted. Of course none of these settings should cause problems, so maybe it's going to vary from server to server.

I also upgraded the driver version for the NIC, applied a BIOS patch and the latest Windows optional update rollup for Hyper-V issues, including a blue screen issue that we had experienced twice in the last week: KB2264080.

Here's the Dell support script I followed:

In a command prompt:

a. netsh int tcp set global chimney=disabled

b. netsh interface tcp set global rss=disabled

b. On each NIC inside the Broadcom Advanced Control Suite (BACS)

i. Disable IPv4 Checksum Offload

ii. Disable IPv4 Large Send Offload (LSO)

iii. Disable Receive Side Scaling (RSS)

. Uncheck the TCP Offload Engine (TOE) checkbox

v. Click Apply

Intel Configuration

a. Open Device Manager

b. On each Intel NIC in Device Manager, disable the following:

c. NOTE: Not every option is available or exist on the Advanced Tab.

i. Offload Receive IP Checksum

ii. Offload Receive TCP Checksum

iii. Offload TCP Segmentation

iv. Offload Transmit IP Checksum

v. Offload Transmit TCP Checksum

vi. IPV4 Checksum Offload

vii. Large Send Offload v2 (IPV4)

viii. Large Send Offload v2 (IPV6)

ix. Receive-Side Scaling

x. TCP Checksum Offload (IPV4)

xi. TCP Checksum Offload (IPV6)

In Windows Server 2008

                                                                                 1.      Start à Run à CMD 

                                                                                 2.      netsh interface tcp set global rss=disabled 

a. netsh int tcp set global autotuninglevel=disable

In the managers Outlook or OWA turn off the message Read options. If the manager uses Outlook as their primary email client and doesn't want to turn off the message Read options because it will affect his/her messages then have them use OWA to view the employees mailbox and turn off the message Read options in OWA.

EDIT

In the OWA options you should have the following three options:

Mark item displayed in reading pane as read
Mark item as read when selection changes
Do not automatically mark items as read

Select the thrid option. Then when the manager uses OWA to read the employee's email the messages won't be marked as Read.