This problem is also occurring for me. It seemed to happen after the latest Widows 10 updates I installed on 10 July. KB4506991 and KB4507453. I tried reverting to a copy of CC557 that I still had but the problem is appearing there too. I suspect something in the Win 10 update has invalidated part of the CC code. Ray
I can't download the portable version either. Using https://www.ccleaner.com/ccleaner/download/portable the link goes to the download page but, instead of starting the download, the page just goes blank. Using https://www.ccleaner.com/ccleaner/builds only shows the standard installer, no portable version. Cleared caches and tried Chrome, Firefox and Edge. No success.