A popular question on many forums goes something like this
Outlook isn't recognized by [application_name]. The error is "Either there is no default mail client or the current mail client cannot fulfill the messaging request. Please run Microsoft Outlook and set it as the default client." When I check the Default Programs, Microsoft Outlook is the default for everything.
First and foremost, when you receive this message while using Outlook 64-bit, try the 32-bit version of Office. While some applications and addins work with the 64-bit version, not all do. Unless you need to open large (2 GB) Excel and Access files, you won't benefit the 64-bit version. Wanting to use the 64-bit version because you use a 64-bit operating system isn't enough reason to use it, if you need compatibility between different applications, you'll need to stick with the 32-bit build.
Repeat: Avoid the 64-bit version unless you have confirmed the add-ins and utilities you want to use will work with it. There is no benefit to using the 64-bit version for typical users - Office is not going to run faster or better. Only those who work with huge (2GB) record sets and spreadsheets need the 64-bit version. The 32-bit version works fine on 64-bit Windows (do not use compatibility mode).
While many applications will work with the 32-bit version of Outlook, some programs will need to be updated before they will work with Outlook 32-bit. This is normal with all new versions of Office.
Note: If you are using an Office 2013 or newer Click to Run suite, add-ins should work with it. some add-ins may need to be updated, but Office or newer applications can run addins. This is the exact opposite of Office 2010 Click to run!
If you sync with a smartphone or pda, you need to confirm your device will sync with the 64-bit version of Outlook.
From Microsoft:
Office provides support for the 32-bit version of Office programs running on 64-bit operating systems by using WOW64, a compatibility environment provided by the operating system that allows a 32-bit application to run on a Windows 64-bit operating system. Using the 32-bit version of Office allows people to continue to use existing third-party add-ins for Office that are 32-bit. The 32-bit version of Office is the recommended option for most users, because it prevents potential compatibility issues with other 32-bit applications, specifically third-party add-ins that are available only for 32-bit operating systems.
Pros & Cons: 32-bit
- Many existing add-ins and programs work with it.
- Can co-exist with other 32-bit Office applications.
- Office has the same memory requirements as Office 2007 but even with 32-bit Office, you can open, edit, and switch among applications much faster on 64-bit Windows than on 32-bit Windows.
- Syncs using WDMC
Pros & Cons: 64-bit
- Supports larger file sizes - over 2GB in Excel and Access
- Most add-ins and Active X controls do not work with it
- Cannot co-exist with 32-bit Office family applications
- Syncing with Windows Mobile devices using WMDC NOT supported
"Click to Run" version
While the click to run Office suite is 32 bit, most add-ins will not work with it because it runs in a virtual space. Users need to install a regular 32-bit suite instead. I don't recommend the Click to Run version, except for users who need two versions of Outlook.
More Information
64-bit editions of Office (TechNet)
Evets Nedrow says
Thank you, Diane. One quick question -- will the Outlook profiles of our 80 users need to be rebuilt? We're going from Office 2013 64-bit to Ofc 2013 32-bit. Thanks again --
Diane Poremsky says
No, they won't lose anything in their profile, not as long as you are using either the same version or are moving up to the next version.
If you downgraded from 16 ro 13, then you would need to make new profiles.
Chris S. says
I am trying to install Business Contact Manager for Outlook 2013 x64 ( only 64 and 86 bit available), however I am running Office 2010 x32. Any ideas on how to get BCM to work??
Thank you.
Diane Poremsky says
You need to use the x86 version of BCM with 32-bit Outlook. (32bit is the same as x86).
nahrafqifahs says
Thank you! Just what i'm looking for. Aid4Mail working fine with 32-bits MSI, MAPI Issues. That why i'm reinstalled with 32-bits.
hugopoelen says
Same situation today. I start in the safe mode. It works for a while, than the ventilator starts revving up and Outlooks is going to restart. but after a restart it comes back in the default settings.
Diane Poremsky says
The antivirus addins are disabled in Outlook? Look in the event viewer and see if it gives you any clues as to what mightbe triggering it.
hugopoelen says
Diane,
It had started Outlook in Safe mode (outlook.exe /safe). It started OK. I could use it to send some messages and reply. But later (I did not use it at that moment) it crashed and restarted again.
I am a bit lost
hugopoelen says
Diane,
Thanks for your fast response.
Could it be that the problems coincide with the change of Virus killer from Norton to ESET.
I have been in the Safe mode sometimes lately and switched of all active add-ins, But it went on after I tried to use the normal set-up. Now I will check the Safe mode again.
Thanks
Hugo
Diane Poremsky says
possibly. Is the ESET addin enabled in Outlook? Disable it.
hugo Poelen says
OOOPS
Must be
I have a 6 pst files linked to Outlook 2013
They are 3.8 Gb, 4.9 Gb, 1.2 Gb and 2.1 Gb and 492 Mb
Diane Poremsky says
The pst file sizes indicate you are using Unicode for at least some pst - if the smaller pst files were created by Outlook 2010 or 2013, they are definitely Unicode as well. Unicode pst were introduced in Outlook 2003 and were the default pst format since them - they can grow to 50GB or more (20 to 50GB is the recommended max).
Hugo Poelen says
Hi Diane,
I am looking to solve my problems with Outlook 2013. since a few months I am struggling to keep it alive ;-). When I start a new email the cpu starts speeding up. And if I am a bit unlucky it stops and starts flashing and finally restarts.
I have a few large pst files collected over the years. I am using SCANPST to repair them nowadays regularly. Therefore I thought that I might run up against the 32-bit threshold.
Any suggestion??
Diane Poremsky says
It only happens when you start writing an email? I assume it also happens for replies? Do you leave Outlook open all the time? (You should.)
Does scanpst find errors? I would stop running it routinely, only run it if outlook tells you to. If it finds errors that need fixed, you need to find the cause, not treat the symptoms.
Does outlook work better in Safe mode? If so, this means one of the support files or addins is causing the problems.
Matan says
Hi Diane!
is there any way to convert PST outlook 32 bit to 64 bit so i wii be able to keep working with my old outlook emails?
Diane Poremsky says
A pst will work in either/both 32 or 64 bit outlook. If the pst was created in Outlook 2002 or older or is marked as "Outlook 97-2002" in properties, you should create a new pst in Unicode format (the default for new pst files) and import the old pst.
Ross Goldstein says
Thank you so much Diane! Is it simply choosing the 32-bit version on the same installation disk that came with the original Office, or do I need to buy a separate, new 32-bit Office? My guess is it is MSI, but I will check. Thanks again....
Diane Poremsky says
Just choose the 32 bit install on your disk - your license covers both 32 and 64 bit builds and both are available on your installation disk.
Ross Goldstein says
How do I switch Outlook 2013 from 64-bit to 32-bit, or do I need to switch out the entire Office Professional Suite. If I do, where can I go to learn how to do it? I am using ACT! as a CRM and it is not compatible with 64-bit, so I can not send emails right out of the software. Thank you!
Diane Poremsky says
You need to uninstall the entire office suite - you can't have mixed bitness. Uninstall Office. You'll need to choose the 32 bit version when you install it. Do you have a subscription version or an MSI? (If you aren't sure which, the msi is 600mb or more, the subscriptions are a small file then install in the background.)
G P O says
To work with PST files of 2-6 GB, for a total of 28 GB, I guess it would have to be noticeably faster with the 64-Bit version, this is correct?
What about MS PST Backup (add-in), or "BlackBerry Link"?
Thanks :-)
Diane Poremsky says
It might be a little faster with 64bit when you have large pst files but I don't think it will be noticeable since they are split into smaller pst files. The backup addin will not work in 64bit outlook, I'm not sure about blackberry. I have some batch file examples on the site that can be used to backup data files. They are easiest to use when you first start outlook, as they can backup the pst then start outlook.
Lucas says
Your are stuck in your old mind with 32bits Office, just like those people who were stuck with their old mind on 3.1 vs 95.
Diane Poremsky says
There is no difference better 32 and 64 bit Office, unless you need support for large Excel or Access files (more than 2 GB). Speed-wise, both are about the same speed. If you don't need large file support, choose based on any addins you need as some only work with 32-bit. Many/most addins now work with 64-bit, but a few don't.
Todd says
Thank you for cutting to the chase and providing sensible tips and tricks that are always practical for my needs! Again, many thanks for all your articles!
Joe Wulf says
I benefit from Excel and Project for 64 bit, so of course I have the full 64 bit office installed. However, Norton AntiSpam FAILS to work with 64 bit Outlook.
Question: Can I have 64bit office installed (minus 64bit outlook) ---AND--- 32 bit Outlook installed instead? Can they co-exist sensibly?
Diane Poremsky says
no, sorry, you cant mix 32 and 64 bit versions. I'm surprised Norton doesn't work with 64bit.