Cannot open interactive tutorial or new project

Hi, I am a beginner in Unity who used Unity 2017.1 successfully in a prior school project and am now trying 2018.2 in a hobbyist capacity on a new laptop.

For some reason, I am experiencing 2 problems: 1) I cannot open the interactive tutorials in the “Learn” tab despite downloading them and 2) I cannot open a project newly created by the installed client.

For 1), whenever I press the “Start” button on any of the downloaded tutorials, all I see is the Unity Package Manager progress bar appear for a brief second, then disappear without a visible trace, with no way for me to determine what happened or why the intended tutorial does not start.

For 2), when I create a brand new default 3d project with no additional assets and then try to open it, the Unity client gives me the following:

3862351--327328--upload_2018-11-7_0-50-12.png

However, I cannot find any ProjectVersion.txt file as suggested in "Your project was last opened with a different setup of Unity" after delete Library and I also couldn’t find the localized launcher typically within such projects, as was my experience during my previous experience.

Can anyone offer any suggestions? I have tried reinstalling Unity 2018.2 multiple times

Hi, just tried installing Unity with antivirus temporarily disabled, now both aforementioned problems no longer occur. If anyone knows how to install without disabling antivirus, pls comment.