cant delete music off iphone 5s (in itunes)

[ThereGoesJB]

I am trying to clean out about half the music on my phone. Normally the easy way would be to go through itunes, select them all and delete.

However itunes wont let me delete, I am on a new laptop after my previous laptop died, my previous laptop was set to "manually manage music and videos" I've never used the "sync" function. So on the new laptop i noticed the "manually manage.." option was not checked, but upon checking it I got a warning stating this iphone was set to sync with another computer, by checking this option the iphone will delete and sync all its contents to this computer.

The point of "manually manage songs" is to NOT sync, why is it doing this, what am I doing wrong?

 

[Shirasaki]

iTunes, at any given time, can only sync, or manage, a single library. I bet iTunes On your new computer cannot find the old library, and thus think you are syncing with another library.

In iTunes, besides regular media files, there is a file called “iTunes library.itl”. This file is the database of your entire library. I am not sure what has happened for this file.

Regarding your problem, well, since I use sync, I may not be able to help you too much. Sorry for that.