I Had this months ago, the 'install in progress' stopped my being able to shut down my mac unless i forced quit with the power button.
Very very annoying.
After months of struggle and having my mac constantly switched on. I found a thread online where others had had a similar problem. I had to download another app, that allows deep search, and remove all system items with McAfee name in it. It solved the problem for a few months.
Then i seem to have paid out another years subscription to McAfee, so i tried the promoted update again. Ever since then the bug is back.
I cant say how annoying it is that to have all my time taken up with this yet again!
Instead of trying to find that thread and go the the same process as last time, im looking for a quicker fix here, or i want my money back. why am i paying for something i keep having to force remove?
I cant believe a company who should be protecting your Mac is the creating the only problem ive ever had with it.
Its also definetley not an 'obscure' problem as there was a whole thread about fixing it online. Also they have much on their own website about fixing the same issue on Windows.