nexus 7 2013 unwanted screens

[nushie]

without known reason i keep getting screens that say , eg:
"speeding up your phone x% on a solid color background
"have cooled your phone x%" solid color, etc.
"cleaning up x"
not like a virus, i've tried uninstalling some apps, also eliminated notifications. its still there.
very annoying esp when surfing or reading email.

any help is much appreciated. thank you,

Len

 

[Hadron]

Have you installed any sort of app that claims to improve performance in any way? This sounds like the sort of junk that Clean Master and similar crapware produces.

 

[Achernar]

I have the same issue. "Speeding", "Cooled", "Cleaning" with Google and Facebook logos/references. Many different such graphics appear every time I use my phone. And during. Any thoughts how I can get rid of this crap?