I noticed the same issue, the problem it seems is when you 'edit' a file it get locked by the application and the google drive auto sync kicks in and creates a conflict file.
I notice this mostly with Photoshop files, as the files can get pretty large and the sync doesn't happen quickly like a simple text file and it cause a lot of duplicates.
My solution: pause google drive while I am working on these files and when done, let them sync.
The answer to all your questions is No
To understand the file system you may like to start with File System Basics.
The three /Library locations are for different purposes though, as you have guessed, there is some overlap.
Briefly, the purpose of each is:
/System/Library: Files which allow OS X to start and run./Library: Other important system and application support files which are not specific to each user.~/Library: System and application support files which are specific to the user.
So files in /Library/Application Support/x are used by all users of application x and those in ~/Library/Application Support/x are specific to the user. Some applications will only use one or the other, whilst some use both.
Moving folders/files between /Library and ~/Library is likely to cause applications to malfunction or system components to fail. Moving LaunchAgents or LaunchDaemons is especially dangerous.
Even worse, touching /System/Library is likely to prevent your Mac from booting!
Also, files inside application bundles must remain where they are - moving them will break the application.
So, in conclusion, don't move folders around as OS X expects files to be in their right place.
Best Answer
This is normal. These programs have been downloaded as virtual disk or
.dmgfiles.For example Mendeley Desktop is a program supplied as
Mendeley-Desktop-1.19.4-OSX-Universal.dmgfile. When you open the downloaded file by default you will see it appear on your desktop and as a removable drive in Finder.Once you have dragged the application to Applications you can eject the virtual disk in Finder and then delete the downloaded
.dmgfile.Note some programs - MS Office for example - are supplied as packages (files ending in
.pkg) rather than.dmgfiles. When you run this type the program is installed without mounting a virtual drive and macOS will automatically prompt you to delete the installer file once done.