It might but then not using ClearType was never a problem until now.
It might be a display problem but then i want to know why and what's causing it.
I don't accept: "it's like that now, get used to it" i don't want to accept (yet).
If it would have been there all the time, it would be normal. This ain't.

Did some more testing after the printing/pdf result.
In Outlook: Only editor and reading panes are effected by the spacing problem. Other parts of Outlook are just fine. The titles on the various e-mail listed in the subject pane do not have the spacing problem, nor do the titles of the mails in the reading pane. It's just the content.
Subject:


Reading pane title of the mail:



Therefore i sended a mail from a webmail to myself but loaded it with Outlook.
The title is OK in the mail list. The title is OK in the reading pane but the text within the mail is not.
Also, the spacing is not always off but occurs more like in groups:

The small a's are grouped in 5 and then there is an extra space.
The capital A's have the same issue (if you look closely you see the legs don't touch after each group).
The b's however are grouped in 2 and then an extra space is added. This goes on 6 times and then a 3th b is added to the next group.
It's different for each letter...

I don't want to go ClearType just yet to solve this because ClearType messes up my colomn settings in Excel.
Some sheets i use just cover the entire screen nicely. With ClearType on they grow bigger which makes i have to scroll and all is not in one view anymore.