Exchange 2007- 2013 Migration - Slow loading of emails/secondary mailbox's

After upgrading to Microsoft Exchange 2013 ( part of the 2 stage upgrade to 2016/2019) i noticed a few problems


The school currently uses roaming profiles so "cached" outlook profiles were not a option so "Online" mailbox's were needed.


1.) Primary mailbox's , Slow to attach large files and sending to multiple recipients. Normal opening of small emails seemed fine

2.) secondary mailbox's seemed even slower


Changing the outlook profiles to "cached" seemed to resolve the issue , but wasn't a solution i wanted to look into due to the profile having to be created every time.


After scouring the migration and install options i couldn't see a solution . Until i read about an issue regarding TcpAckFrequency on the client's side.


Solution:

http://support.microsoft.com/kb/2020559/en-us

1.Start Registry Editor (Regedit.exe).

2.Locate and then click the following registry subkey:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces

the interfaces will be listed underneath by automatically generated GUIDs like {064A622F-850B-4C97-96B3-0F0E99162E56}

3.Click each of the interface GUIDs and perform the following steps:

a. On the Edit menu, point to New, and then click DWORD value.

b. Name the new value TcpAckFrequency, and assign it a value of 1.

4.Exit the Registry Editor.

5.Restart Windows for this change to take effect


This solution did work , but shouldn't be required as exchange has been out for a number of years and couldn't believe Microsoft would leave an apparent bug. After researching a bit more i actually found out that the bug was indeed a Vmware "Tools" problem .


The solution was solved by modifying the install on the exchange server of the "Vmware tools" . If you modify the installation and remove the following :

NSX File Introspection Driver

NSX Network Introspection Driver


exchange will now work as expected !