Elements portable 500gb not taking files on mac

I have an Elements portable 500gb drive that works perfectly on my home PC and my friend’s Mac laptop. Is there any reason that it would not be allowing me to add files from my school Mac computer?

now a different program is saying that it is somehow locked. I cannot add files, but i can take off

You may need more rights from the Mac computer you are using at school.

You may have a security locked on this drive that prevent you from being able to add file to it.

Unlock the security or password before attemting to add files.

I have same problem !! 

and I use it home with my Mac but it’s not work I can’t add files to it : it’s said ( The Elements not modify ) !! how I can make it work !! 

When using any external drive with Time Machine on the mac computer.

It changed the file system to Apple partition.

That is why the drive can not add file to it from a PC computer which use FAT32 file system.

The solution to this is:

Do not use Time Machine as your back up utility.

Just drag and drop file yourself.