i had the same issue
lots of techies leave half useless help, so here is my fixed
stolen from one of the above and explained for dummies:

>>>This typically only happens if you attempted to install any version of CB other then 1.7 then try to install 1.7. Results in corrupt menu database rows and won't allow CBs to create.

>>Please run the below queries directly on your database then reinstall CB 1.7.
explained: go to your hosting cpanel (control panel (where you setup your emails etc))
find phpadmin
click on your database (joomla_jo1xx)
the 2nd tab op top should be SQL
(this is like a command prompt for us windows users)
simply copy each line below (I did one at the time, you might be able to do both)
and paste it into the window and hit go
it'll ask you of you want to do, say yes

DELETE FROM `jos_assets` WHERE `name` = 'com_comprofiler';
DELETE FROM `jos_menu` WHERE `path` LIKE '%comcomprofiler%';

no reinstall com_comprofiler and the admin menu is there.
worked for me

thank you, I hope this work