MAPISendMail Error 26

April 6, 2018

Recently I ran into an Error 26 – MAPISendMail Failed

Using a Windows 10 Pro x64 and an Outlook 2010 installation.

This Error was triggered if an external Application (FormDesigner) was trying to send an Email using the users MAPI Profile in Outlook.


Solution :

1. Close Outlook

2. Locate folder :

x64 : C:\Program Files\Common Files\System\Msmapi\1033 or

x32 : C:\Program Files (x86)\Common Files\system\MSMAPI\1033

3. Rename MSMapi32.dll to MSMapi32.old

4. Open outlook again. Outlook will repair the file again.

5. Test it, the Email work again.

And the Error will be gone too Smile

Enjoy !

Outlook – Migrating AutoComplete cache from Outlook 2010 to 2007

September 19, 2014

I seen many blog on the net about how to migrate the Email AutoComplete list for 2007 to 2010.

I will not repeat that here there’s already enough on the net to find for yourself.

But let’s presume the following. A PC crashes and you got a spare on around. But the user was using OL 2010 and now you handed over to him an OL 2007 ?

And he want to have all his email addresses migrated because does not want to type it all over. Sad smile

Solution :

In OL 2010 there is something that is called “Suggested Contacts”


Since the AutoComplete file format changed between the 2 Versions of OL. You just can’t backport it.

OL 2007 and before used a ProfileName.NK2 file


OL 2010 uses a Stream_Autocomplete_*.DAT file

But wait, we could pick up the “Suggested Contacts” and Export them to a PST file and then import them again in OL 2007 as contacts ?


Just go to OL 2010 File –> Options –> Advanced –> IMPORT (for Export)

Or go to File –> Open –> Import ( For Export )


Select Export to a File –> PST file –> Suggested Contacts


And so on, at the end you will have a PST file with all you Autocomplete E-mail Addresses in it as Contacts.

Now we can IMPORT it again in OL 2007. It’s not quite the same as autocomplete.

But the users can at least find back all his email addresses he did not have before.

1. Composing a new E-mail

2. types a part of the name, or email address

2. Next Press Ctrl + K and it will bring up the list of available email addresses.

You just made a user happy Smile


Outlook – 2007 – Search problems

May 28, 2014

Again issues with an older version of Outlook. Suddenly when using the quick search it did not return results from the mailbox store (OST). Only returned results from the Archive file (PST).

When reading on the internet there are many post of people having the same issues with even newer releases of OL.

You will see an event ID 36


Outlook Search has encountered an error and is temporarily disabling indexing for store C:\Users\xxxx\AppData\Local\Microsoft\Outlook\outlook.ost (error=0x800706ba).

I tried the most obvious first :

The solutions work for a higher version as well I guess.

1. Re-indexing

Close OL first. Go to Control Panel\All Control Panel Items\Indexing Options

Start the rebuild


Open OL again. But no success ?

2. Re-install Office 2007 SP3

You can’t re-install without uninstalling. And by default you can’t uninstall Sad smile

So first you have to download the MS 2007 Office SP Uninstall Tool.

Running “oarpman /help” from the command line.

You will see that you can run the /report switch to list the installed patches


To uninstall you need to use the /remove + release name

ex: oarpman /remove 012SP3

So after getting it uninstalled and reinstalled SP3 again. I opened OL. But no success still the same Sad smile

3. Running Office REPAIR

I though why not run the repair. Go to Control Panel\All Control Panel Items\Programs and Features and select Change


But again I ran into an Error 1935, and the repair did a full rollback !

So first had to solve this issue.

This PC did not have the Microsoft .NET Framework 4 Client Profile so I ran the Microsoft .NET Framework 4.5.1 repair


Reopened OL again, but no luck so far !

4. Check OL Logging

1. Turn on Outlook logging (Tools -> Options -> Other -> Advanced Options -> Check “Enable logging” -> Reboot Outlook


2. Go to your Notes folder and modify a note.  This will re-trigger indexing for that item.

3. Use Outlook’s Indexing Status to wait for the count to get back to 0.

4. Go to “%temp%\outlook logging” and look at the log file for your store.
It will have a recent timestamp and will have a name in the form “store.pst.log.”  or “outlook.ost.log”
Take a look at that log file for errors.

5. Try to search for the modified item.

6. Turn off Outlook logging (since it has a performance impact) and restart Outlook.

Did not bring me a lot of information ?


5. Last step

I stopped the Windows Search Service.


Go to OL –> Tools –> Instant Search –> Search Options


Unchecked BOTH stores, closed OL.

Restarted the Windows Search Service

Opened OL and check both options again.

Surprise it was working again, as simple as that. Smile

I am still not sure if the last steps solved the issue are all that steps in total ? Anyhow it took a lot of efforts to get it going again.

Outlook – 2007 Connection Issues

January 29, 2014

I was experiencing an issue with a user having issues after migration of of exchange 2003 to exchange 2010.

When starting outlook 2007 it took 5 minutes before outlook was properly started Sad smile


Outlook was hanging all time.

After getting started on a wrong foot. I was thinking there was something wrong with his profile. After recreating from scratch it did not solve the issue ?

After my search on the net I tried several steps, untill this solved the issue.

It was an Add-on that was bugging me.

In Outlook 2007 go to Tools –> Trust Center –>



Go to Manage COM Add-ins


Disable all Add-ins. But notice that in some case you get this message


To solve it start Outlook as Administrator


I restarted and disabled all of them.

YES the problem was solved ! Smile

Now you can test by activating 1 by 1 to see which is giving you a headache.

This approach might apply also for other versions of Outlook.

Outlook – Migration Steps

November 27, 2013

This is a shortlist the remind you on some steps to follow a good Outlook migration after you did an Exchange Migration.

1. Test if the use can access the OWA first BEFORE you delete his Outlook Profile ! To make sure the server account is OK for this user.

2. Next Export all MAILS / CONTACTS / NOTES / TASKS to a PST file

3. Copy his / her AutoComplete list

=> %APPDATA%\Microsoft\Outlook

C:\Users\UsersName\AppData\Roaming\Microsoft\Outlook\xxxx.nk2 (xxxx= Profile name)

4. Copy the Auto Signatures

Go to =>


5. Delete all offline Address Books (OAB)

=> %APPDATA% -> \Local\Microsoft\Outlook

And delete all *.OAB (offline address book) files

6. Configure a new PROFILE
    A. Close Outlook

B. Go to Control Panel -> Mail (32-bit)

=> Delete all Outlook Profiles

C. Create a new PROFILE with a new name

7. Import his / her mails / contacts etc. from the previous exported PST file

8. Import the Auto-Complete List :
Do one of the following:
=>  Windows 7  Click Start {picture}. Next to the Shut down button, in the Search programs and files box, type outlook /importnk2 and then press Enter.

=> Windows Vista Click Start {picture}. Next to the Shut Down button, in the Search box, type outlook /importnk2 and then press Enter.

=> Windows XP Click Start {picture}, click Run, type outlook /importnk2 and then press Enter.

9. Add the Auto Signature  and the rest of the configurations settings.

Outlook – Distribution Groups don’t show members

November 27, 2013

After migrating an Exchange Server I noticed that when I added an Distribution Group to my Mail I could not see the members of that group ?

Error when clicking the + sign to open up the members window.

Cannot perform me requested operation. The command selected is not valid for this recipient. The operation failed.


Solution was simple.

Close Outlook first, next go to the folder %APPDATA% –> Local\Microsoft\Outlook


And clear all *.oab Files Open up sync again and everything is working fine again.

Outlook – Lookout search tool Add-on

January 11, 2013

I was so unpleasantly surprised to see this outlook disappear, when Microsoft took over the company that build it.

Many years back it was distributed for free, but development was not supported anymore Sad smile I use it everyday and can’t miss it, just like many of my colleagues.


This search tool is versatile and very fast to search Mail folders, Archive PST files, local files and network shares. What can a user want more ?


Lot’s of filter possibilities as well as custom filter settings.

But since outlook 2007 and higher was released you where not able to install the add-on anymore ! It would crash.

But … somewhere on the internet I found a workaround how to fix this.

After installing the Add-on you will see this error appearing.


The problem is that Outlook 2007 and higher ships the Outlook 2007 Office PIAs by default.  To Solve it open a command shell (as administrator), and issue the following commands:

Go to C:\Windows\Assembly\GAC

Rename both file to .OLD


Exclude the DELETED ITEMS folder if it crashes when indexing.


PS: If you can’t find the tool anymore on the net drop me a message.