XCode not updating via Mac App Store. Asks "Sign in to (null) to update..."

Quit the App Store and trash these:

~/Library/Caches/com.apple.appstore
~/Library/Caches/com.apple.storeagent
~/Library/Preferences/com.apple.appstore.plist
~/Library/Preferences/com.apple.storeagent.plist
~/Library/Cookies/com.apple.appstore.plist

Look in your Downloads folder for anything Xcode:

HD/User/Documents/Downloads.
If it’s there delete it.

Look in your Applications folder for Install Xcode.app.
If it’s there it might be complete. Try to open it.
If not, delete it.

Start App Store and see if it says install.

Next step is to delete cache files.
I use Snow Leopard Cache Cleaner:

http://www.macupdate.com/app/mac/9503/snow-leopard-cache-cleaner

Thanks ... Ken

Same here.

I tried deleting cache and library files suggested for NO LUCK.

What a pile of crap! I miss my windows PC.

Message was edited by: Sith.Lord

I have the very same problem: I bought XCode 4.0 from the Apple Store and now I can't update to 4.0.1... "Sign in to (null)" is the message I get

Hopefully someone can look into this

Alex

I uninstalled Xcode 4.0 and then downloaded Xcode 4.0.1 from App store.

It is a pain in the ***.

+anyone else facing this same issue?+

Yup exactly the same issue and situation, only have one AppleID and am logged in correctly.

+please suggest how to update it.+

Don't know at this stage, have reported the problem to Apple and iTunes folks so hopefully they will sort it out soon.

easiest way to upgrade is to move the 'install xcode' app, reopen the app store and reinstall xcode.

Doesn't work ... same message.

Just had the same problem. Fix seems to be to upgrade to the latest OS X 10.6.7 (and presumably hence and App Store upgrade), then delete the old XCode installer. THEN clear your trash can.

I seem to be having the same problem. I ask to update XCode 4 and it tells me I need to log in with another account (not null as some others reported). I just trashed the "Install Xcode" app and now the App Store shows Install instead of Update. Downloading now. Sure hope this works and would really like to be able to just Update rather than trash and install.

I'm having this same issue too.

I have to say, across my two Macs, I haven't had a single XCode 4 install go smoothly. This has been the worst experience with dev tools I've had over the past 10 years, and it's the first time I had to pay for them (Aside from my OS X license).

Apple: Please, Please, institute some QA on this, I've spent more time trying to get Xcode to install than I've had to actually use it to write code.

Update: I upgraded to 10.6.7 and this went smoothly.

Whew 🙂