Hi,
I can’t see Package Manager menu on window menu.
•I uploaded to the last version, uninstalled/installed Unity
•Turned off my Windows Firewall
•I reset packages to default
But still doesn’t fixed 
https://i.hizliresim.com/9aj6RZ.jpg (Screenshot)
I also getting these errors when I create a new project.
When I move the Packages folder to Assets folder, the warnings disappear but still can’t see the Package Manager menu.
Please help me.
Upupup
Okay, I solved the problem. Thank you guys for your help! 
If you have same problem;
Download Revo Uninstaller
Uninstall All The Unity versions and Unity Hub with Revo Uninstaller (You can back up your projects)
And remove all of the regedit datas.
And load Unity again. (I downloaded without Unity Hub. But you can download within Unity Hub if u want.)
Thanks.
Hi @retropxgames ,
Glad to hear you solved your problem! However, we wouldn’t recommend to other users that they uninstall Unity as a solution to a Package Manager problem.
I can’t tell exactly what the problem was from the screenshot because the link is broken but it was likely an issue caused by package incompatibility. The Package Manager window (and hence the Window > Package Manager menu item) were provided by a package. As a result, if this package could not be loaded in the project due to a conflict or compilation errors, you would not see the menu item. A workaround is usually to reset packages to defaults (which you tried) or find a way to resolve the packages by manually editing the project manifest (which should be a last resort).
The issue of the missing Package Manager menu item has now been fixed as of 2019.2 because the window is built into the editor instead of being its own package.
Regards,
Sam
