German Umlauts (ä,ö,ü,ß) corrupt in HTML Mails sent with Outlook 2013 and OXtender 2 for OpenXchange

Today i noticed that HTML Mails I sent from Outlook 2013 looked like this on the receiver side:

�ffentliche �bereinstimmung m��te sein

The german umlauts (special characters)  were somehow misinterpreted as non-printable characters.
 

The original text was:

"Öffentliche Übereinstimmung müßte sein"

How-I-fixed-it:

Looking at the raw mail source content i recognized, there was a lot of css-stuff in mail which seemed to be added by Outlook automatically.
osoft-com:office:office" xmlns:w=3D"urn:schemas-microsoft-com:office:word" =
xmlns:m=3D"http://schemas.microsoft.com/office/2004/12/omml" xmlns=3D"http:=
//www.w3.org/TR/REC-html40">ft Word 15 (filtered medium)">
link=3D"#954F72">

=EF=BF=
=BDffentliche =EF=BF=BDbereinstimmung m=EF=BF=BD=EF=BF=BDte sein=

-->
I found out, that there's an option in Outlook to tell it to use CSS for formatting or not.

I disabled this option and my HTML mails look OK now.

Outlook 2007 Inbox shows blank mails with no date that cannot be deleted

Today i cleaned up my Outlook 2007 inbox and deleted some old mails. Suddenly a couple of mails in the list were shown blank (No sender/receiver, no subject) with the date "None".
Scrolling through the inbox list the scroll stuck as soon as i came to those entries. I could not select the entries nor delete them.

How-i-fixed-it:
I seems like the pst folder went corrupt.
I found the solution here: http://office.microsoft.com/de-de/outlook-help/durchsuchen-und-reparieren-fehlerhafter-outlook-datendateie-HA010075831.aspx

Office comes with a tool called "SCANPST.EXE". It's located under C:\Program Files\Microsoft Office\Office12

Close Outlook and start the tool. Then select the .pst-File that seems to have issues and the the tool repair it. I automatically creates a backup of the file before modifying it.

I let the tool repair the .pst file and my inbox was fine again.