first, close your cc desktop app.
then, rename the opm.db file by:
navigate to the OOBE folder.
Windows: [System drive]:\Users\[username]\AppData\Local\Adobe\OOBE
Mac OS: /User/<username>/Library/Application Support/Adobe/OOBE folder
and rename the opm.db file to opm_old.db, eg
finally, launch your cc desktop app.
I've done this but I'm still getting a white screen.
uninstall everything cc including preferences, https://helpx.adobe.com/creative-cloud/help/uninstall-remove-app.html
then uninstall the cc desktop app, https://helpx.adobe.com/creative-cloud/help/uninstall-creative-cloud-desktop-app.html
clean your computer of cc files per http://www.adobe.com/support/contact/cscleanertool.html
remove your opm.db file
restart your computer (don't skip this)
reinstall the cc desktop app, https://creative.adobe.com/products/creative-cloud.
if you're unable to install the cc desktop app at this stage, use an administrator account (solution 3 here, https://helpx.adobe.com/creative-cloud/kb/creative-cloud-missing-damaged.html)
use the desktop app to install your cc programs/trials