Windows Mail Slow

How to Fix a Slow Windows Mail
This will show you how to fix four different causes for Windows Mail being slow.
How to Fix a Slow Windows Mail

information   Information
This will show you how to fix four different causes for Windows Mail being slow.
Note   Note
Check for each of these causes and follow the steps below for how to fix the issue for each of these.

Known Causes


Antivirus Program

You have the email scanning options turned on in your antivirus program or your antivirus program is not compatible with Vista or Windows Mail.

Restricted Sites List

Some programs (ex:anti-Spyware) may add a large number of entries to the Internet Explorer restricted sites list. This can cause a severe performance problem in Windows Mail after installing the KB931768 Windows update before SP1 is installed. The slowness comes from Windows Mail having some kind of conflict with the update and the spy program making it read through the long list of restricted sites first.

To Many Contacts

For each 100 contact files in your Contact folder (name and email address totaling 2KB) there is a 0.25 second delay imposed by Vista for when you Create, Reply, Forward, or AutoFill a message. (EX: A 2 to 3 second delay for every 1000 contacts) The timing delay will vary due to processor speed and size of contact file.

To Many Messages

If you store or have a ton of messages in a mailbox folder (EX: Inbox), it can cause a delay while opening it.

Large Attachment

If you try to attach or receive a large file size attachment, then this can cause a slow receive or send depending on your internet speed.

Database Issues

The Windows Mail database may need to be compacted and repaired.

Tip   Tip
A Workaround:
  • Open Windows Calendar from within Windows Mail. (Tools -> Windows Calendar)
  • Close Windows Calendar after a minute.

How to Fix the Antivirus Program Issue

1. For how, see the section titled FIRST in Problem One of this link below:

How to Fix the Restricted Sites Issue

1. To Fix the Restricted Sites Issue
A) Click the Download button below to download the file below, and save it to your desktop.​

B) Go to step 3.​

2. To Undo the Restricted Sites Fix
A) Click the Download button below to download the file below, and save it to your desktop.​

3. Right click on the downloaded .reg file, and click on Merge.​
4. Click on the Run, Continue, Yes, OK if prompted.​
Note   Note
This will add or remove the winmail.exe value in the registry location:
Note   Note


How to Fix the To Many Contacts Issue

NOTE: This is more of a workaround than a fix, but it works.
1. Simply go the Contacts folder and reduce how many you have. You can either delete or relocate these contacts to a different or new personal folder. (EX: C:\Users\(your username)\Contacts2)​
NOTE: The default Contacts folder is located here: C:\Users\(your username)\Contacts
2. You can then just simply browse to this new location when you click on Tools and Windows Contacts in Windows Mail to navigate to and select your other contacts.​

How to Fix the To Many Messages Issue

1. Simply delete the messages when done with them.​
2. If you want to store messages, then use Windows Mail Import and Export Messages feature to save the messages in a separate new folder on the desktop or in a personal user folder.​
NOTE: For how, see: Windows Mail - Messages

How to Fix the Large Attachment Issue

1. For Sending
A) Make the attachment smaller by putting it in a ZIP file.​
B) Break the attachment up and send it in separate messages.​

2. For Receiving
A) Ask the sender to do step 1.​

How to Fix the Database Issue

1. If open, close Windows Mail.​
2. Open Task Manager, and End Proccess any instance of winmail.exe if listed.
NOTE: You will use OPTION TWO at that link.​
3. Do the Compact Database and Repair Database with the free program WMUtil.​
NOTE: Be sure to follow all directions for the program at that website.​
That's it,

Last edited by a moderator:
Shawn Brink


I had this problem of very slow windows mail and notice that i got an update at the same time as the problem occurred after someone else told me.
The updated was KB905866 for junk mail i have since deleted it and now the mail is ok.
Hope this is usefull my os is 32xvista home prem.
Please can someone tell me if the above advice about "regedit" can be used on my system if needed or only on the 64xbit OS
Hi Niall,

Yes it can be used on the 32 bit Vista to. All of these slowness problems seem to fall back to the "restricted sites list".

Hi Lanscomm,

I'm sorry, but my default location has always been C:\Users\(your username)\Contacts. I have done several reinstalls and such and this has always been the case for me. Have you created a new Contact folder in the Desktop folder by chance when you were applying your solution?

While using Windows Mail if we click on Create New Email/Forward Email/Reply All takes a lot of time to 'Open', when option is ticked to automatically complete email addresses, BUT when the option is unticked to automatically complete email addresses, the email opens immediately however then it takes a lot of time to complete the send process, while searching for the email id from the address book
Hello Taovictor, and welcome to Vista Forums.

Thank you for reporting this. The download is back now and ready for download.

So far the recommended fixes have helped in speeding up the program However, it still leaves much to be desired. with Outlook Express none of these fixes were necessary. The quantity of email addresses or messages were not a factor. It was a wonderful program that has been virtually destroyed. For instance, selecting a group of addresses to send emails puts them in the TO: window when I want to have them in the BCC: window. I have to cut and paste to get them into BCC. I am only interested in email addresses not in all the other Contact info. and I believe that is the case for most users.

Windows Live Mail is even worse because you cannot easily group names. In my Real Estate business I need to group names of agents, clients, prospects etc. to send specific messages to.

I would like to use Thunderbird but I have no way of transferring the many folders of segregated messages in the same format to it. I am also not certain if the segregation of email addresses into groups can be transferred in the same format. Vista has created hugh problems for me but I am now stuck with it.

Any suggestions?

Thanks much for your help so far, if it wasn't for people like yourself I don't where users like me would turn.

Ben Cerruti (a senior citizen with a BSEE degree but software illiterate)