Can't Install Creative Cloud on New iMac/Yosemite

I was ultimately successful. I had to do a FULL de-install of CC. It's not documented, so here's the log from my chat with Adobe Support. It worked!

Midhun: We appreciate your patience and regret the inconvenience due to high wait time.

dkaye: Hi, Midhub!

dkaye: Midhun!

Midhun: Please allow me a moment while I look into your account & verify the details.

Midhun: I understand that you are facing blank screen issue for the Creative Cloud Desktop App, is that correct?

dkaye: Correct.

Midhun: Thank you for confirming the issue.

dkaye: Not blank screen. Blank wiondow in the CC app.

Midhun: I will be glad to check and help you with this.

Midhun: I see that we have to perform some troubleshooting steps to resolve this issue now.

dkaye: ok

Midhun: On Mac, Click on Finder>Go>Go to Folder, then type ~/library, press enter.

dkaye: ok

Midhun: Please navigate to: Application Support> Adobe.

dkaye: ok

Midhun: Please look for the folders below and delete them if they are present:

Midhun: 1. OOBE.

Midhun: 2. AAMUpdater.

Midhun: 3. AdobeApplicationManager.

dkaye: Deleted 1 & 2. #3 not there.

Midhun: Now please click on the Finder once again then on Go>Go to Folder. This time please type /library and press enter.

dkaye: ok

Midhun: Navigate to: Application Support> Adobe.

dkaye: ok

Midhun: Please look for the folders below and delete them if they are present:

Midhun: 1. OOBE.

Midhun: 2. AAMUpdater.

Midhun: 3. AdobeApplicationManager.

dkaye: ok

Midhun: Click on Go>Utilities.

Midhun: Please look for the folders below and delete them if they are present:

Midhun: 1. Adobe Creative Cloud.

Midhun: 2. Adobe Application Manager.

dkaye: Go>Utilities doesn't work.

dkaye: Do you mean Applications/Utilities?

Midhun: Yes, you are correct.

dkaye: ok

Midhun: Do you have the Cleaner tool on your machine?

dkaye: yes. should I run it again?

Midhun: Please mark the option "All" on the top  drop down menu and perform the following steps:

Midhun: Select Creative Cloud desktop application and then select 'cleanup selected'.

Midhun: Select Adobe application manager for Mac OS X 10.6 and then select 'cleanup selected'.

dkaye: Creative Cloud didn't appear.

dkaye: Application Manager cleaned ok.

Midhun: Did you mark the option "All". ?

dkaye: The list is now empty.

dkaye: Yes, All.

Midhun: Okay.

Midhun: Close the Cleaner tool.

Midhun: Download latest version of Creative Cloud desktop using below link:

dkaye: ok

Midhun: Click here.

dkaye: ok. ready to run.

Midhun: Please download and install it.

dkaye: downloading...

Midhun: Okay.

dkaye: Ha! Now I get the login screen. Much better! I'll log in.

Midhun: Please let me know.

dkaye: Hooray! Login successful and I see all the apps. Looks like I can download/install them now, correct?

Midhun: Excellent!!

Midhun: Yes, you are correct.

Midhun: Is there anything else I can help you with?

dkaye: Ok, then we're all done. Thanks so much for your help!!

Midhun: You're most welcome and it is my pleasure to help you today.

Midhun: You may receive an email that will contain a link to complete an optional survey to provide your feedback on the support experience. Your feedback is very much appreciated.

Midhun: Thank you for contacting Adobe. Good Bye.