PUP.DataMngr is a specific detection (Potentially Unwanted Program).A potentially unwanted application is a program that contains adware, installs toolbars or has other unclear objectives.

PUP.DataMngr it’s technically not a virus, PUP.DataMngr got on your computer after you have installed a freeware software (video recording/streaming, download-managers or PDF creators) that had bundled into their installation this browser hijacker.

It is Potentially Unwanted Propgram is also bundled within the custom installer on many download sites (examples: CNET, Brothersoft or Softonic), so if you have downloaded a software from these websites, chances are that PUP.DataMngr was installed during the software setup process.

You should always pay attention when installing software because often, a software installer includes optional installs, such as this PUP.DataMngr browser hijacker. 

1:Be very careful what you agree to install.

2:Always opt for the custom installation and deselect anything that is not familiar, especially optional software that you never wanted to download and install in the first place. 

3:you should not install software that you don’t trust.

iSheriff Web Security detects and removes this successfully.