As Microsoft sprints to the finish line for the General Availability of Windows 8 on October 26, it is updating all of the built-in apps.
For the most part, that process has gone smoothly. But one app—or, more accurately, one intricately related collection of apps—has been giving some users fits.
There are four apps in the Windows Communications package: Mail, People, Messaging, and Calendar. Those four apps are installed (and uninstalled) as a group. That integration is what enables you to use a single linked set of accounts to send email, carry on instant messaging threads, and update multiple calendars, all using an address book (People) whose contents are drawn from multiple services
The most recent update, delivered last week, appears to have broken some of the core features of that collection.
This thread contains a multitude of reports, and I’ve seen confirmation on Twitter and via email from readers. The most common symptom is that AutoComplete in email address fields doesn’t work.
The official answer, from a Microsoft support rep, acknowledges the issue:
Thank you for trying the Mail App update and reporting this issue. We recently became aware of this problem and the approriate people are currently looking into it.
The support post suggests two ways to work around the issue
- Go through the People App and send email to the contact you desire.
- Put People App in Snap mode with Mail App in fill mode and copy/paste the email addresses you want from People into the Compose window.
A more permanent workaround is to uninsall the Mail/Calendar/People/Messaging App suite, reboot your computer and reinstall the latest version (16.4.4391.1005) of the suite directly from the Store (beware that you will lose all your saved drafts and will have to resync all your emails for all accounts with this workaround).
I expect this issue to be resolved by the time Windows 8 is officially available to the public. I’ve asked Microsoft for comment and will let you know when I hear back.
Ed Bott (@ wordpress.com) 
When I updated I lost that ability as well (blank fillin field on Mail). I uninstalled and reinstalled. Problem solved but… I can count glitches like this all over the OS. Annoying for me a techy, but average joe will have a hard time unless he has a good english speaking tech person to talk to. I wonder if Microsoft Stores will help folks with issues like this for free over the phone like some of the Apple Stores do? That would be huge.
I haven’t had any of those issues, which worries me. Why does that worry me? I haven’t had many bugs with Windows 8 yet! I must be doing something terribly wrong!
I am running Windows 8 and this is the primary bug that bothers me so far.
I tried uninstalling and reinstalling the app but autocomplete of e-mail addresses is still not working. The workarounds (copy and pasting, or selecting from the address book) are tedious.