Today I have received the update 5.26.5937 (free version).
When trying to install (= updating the december2016-version), I get the error-message that this free version of CCleaner is not compatible with my recent version of Windows 10 on my x64-system.
After deleting the CC-version of last month (as recommended by Piriform itself), I tried a fully clean installation of 5.26.5937, and guess what : this newest version is also not W10-compatible.
Last week the automatic Windows-update of Jan. 11th, 2017 was succesfully installed on my x64-system. The update contains: (KB3213986), (KB3213986) and (KB3214628).
I'm sorry this has happened - can you please tell me if you have renamed the installer? The installer name should remain as it was when you downloaded it to ensure a successful install - ccsetup526.exe
I had the same problem as ranti999. Ever since CCleaner first came out I changed the setup file name to include the build number (ex. CCleaner Pro-5265937-Setup.exe) and have never
had a problem installing it. I change the setup name on all of the applications that I use including Microsoft updates with no problems except for this latest verion of CCleaner.
for the last few build releases of Windows 10, MS now looks for the string ccleaner in a filename and if found, blocks the install.
in another post it states Piriform and MS are in talks to remedy this.
I'm not sure if it just looks for the string at the start of the filename or anywhere within it, but if you want to change the name you could use the original name of CrapCleaner perhaps.