I have written an Outlook add-in using C#.NET using the Outlook XP PIA's.
The add-in puts a toolbar with buttons on the Explorer and most Inspector
windows, amongst other things.

When this add-in is loaded on a machine with Visual Studio 2005 installed on
it, users experience problems in Outlook that do not appear to be related to
the add-in directly. For instance, if they start a new email message and
click the "To..." button, they get the error "The messaging interface has
returned an unknown error. If the problem persists, restart Outlook.". When
they try to open a recurring calendar appointment, they get the error "Can't
open this item. The operation failed".

If the add-in is nor loaded, Outlook behaves normally. Also, if you
uninstalled the SQL Server 2005 that was installed with Visual Studio 2005,
Outlook seems to behave normally.

I would not like to tell my users that they have to uninstall SQL Server
2005, so I am hoping to find an explanation that is more specific than this
and hopefully a better workaround. Any help is appreciated. Thanks in
advance.

Michael

Well, I isolated it to SQL Server. If you install SQL Server (I downloaded
SQL Server Express for this test), it conflicts with the add-in, so it has
nothing to do with Visual Studio itself. Any ideas anyone?

Michael

"Michael" wrote in message
...
I have written an Outlook add-in using C#.NET using the Outlook XP PIA's.
The add-in puts a toolbar with buttons on the Explorer and most Inspector
windows, amongst other things.

When this add-in is loaded on a machine with Visual Studio 2005 installed
on it, users experience problems in Outlook that do not appear to be
related to the add-in directly. For instance, if they start a new email
message and click the "To..." button, they get the error "The messaging
interface has returned an unknown error. If the problem persists, restart
Outlook.". When they try to open a recurring calendar appointment, they
get the error "Can't open this item. The operation failed".

If the add-in is nor loaded, Outlook behaves normally. Also, if you
uninstalled the SQL Server 2005 that was installed with Visual Studio
2005, Outlook seems to behave normally.

I would not like to tell my users that they have to uninstall SQL Server
2005, so I am hoping to find an explanation that is more specific than
this and hopefully a better workaround. Any help is appreciated. Thanks
in advance.

Michael

I don't know, I have VS 2005 and SQL Server Express installed on a few
machines here with no problems with Outlook addins. Is your addin code
referencing SQL Server in any way?

I haven't tried any addins in a setup like that which use the Outlook 2002
PIA's however, my setups all have the Outlook 2003 and/or the Outlook 2007
PIA's installed.

--
Ken Slovak
[MVP - Outlook]
http://www.slovaktech.com
Author: Absolute Beginner's Guide to Microsoft Office Outlook 2003
Reminder Manager, Extended Reminders, Attachment Options
http://www.slovaktech.com/products.htm


"Michael" wrote in message
...
Well, I isolated it to SQL Server. If you install SQL Server (I
downloaded SQL Server Express for this test), it conflicts with the
add-in, so it has nothing to do with Visual Studio itself. Any ideas
anyone?

Michael

No, my add-in code is not referencing SQL Server in any way.

What's strange is that the errors occur in operations where the add-in is
not even involved, such as pressing the To... button on a new message.
There is no visibility to this action from an add-in.

I also believe it's either related to the Office XP PIA's or perhaps
something related to the .NET Runtime that is changed when you install SQL
Server. The add-in runs fine on 100's of computers, unless SQL Server is
installed. It's hard to imagine that SQL Server would have any impact on
the Outlook API, so my thought was .NET, but I don't know what SQL Server
changes related to that either.

Are any of the add-in's running at your site built using .NET?

Michael

"Ken Slovak - [MVP - Outlook]" wrote in message
...
I don't know, I have VS 2005 and SQL Server Express installed on a few
machines here with no problems with Outlook addins. Is your addin code
referencing SQL Server in any way?

I haven't tried any addins in a setup like that which use the Outlook 2002
PIA's however, my setups all have the Outlook 2003 and/or the Outlook 2007
PIA's installed.

--
Ken Slovak
[MVP - Outlook]
http://www.slovaktech.com
Author: Absolute Beginner's Guide to Microsoft Office Outlook 2003
Reminder Manager, Extended Reminders, Attachment Options
http://www.slovaktech.com/products.htm


"Michael" wrote in message
...
Well, I isolated it to SQL Server. If you install SQL Server (I
downloaded SQL Server Express for this test), it conflicts with the
add-in, so it has nothing to do with Visual Studio itself. Any ideas
anyone?

Michael

Yes, I have a number of addins built with .NET running here but they're all
for Outlook 2003 or 2007 and don't use the 2002 PIA's. All were built with
either VS 2005 or VSTO Cypress.

--
Ken Slovak
[MVP - Outlook]
http://www.slovaktech.com
Author: Absolute Beginner's Guide to Microsoft Office Outlook 2003
Reminder Manager, Extended Reminders, Attachment Options
http://www.slovaktech.com/products.htm


"Michael" wrote in message
...
No, my add-in code is not referencing SQL Server in any way.

What's strange is that the errors occur in operations where the add-in is
not even involved, such as pressing the To... button on a new message.
There is no visibility to this action from an add-in.

I also believe it's either related to the Office XP PIA's or perhaps
something related to the .NET Runtime that is changed when you install SQL
Server. The add-in runs fine on 100's of computers, unless SQL Server is
installed. It's hard to imagine that SQL Server would have any impact on
the Outlook API, so my thought was .NET, but I don't know what SQL Server
changes related to that either.

Are any of the add-in's running at your site built using .NET?

Michael