[SOLVED] Seagate STDR1000100 with Mac 10-9-4 'Disk not ejected properly' pops up

[exasperation]

It backs up OK but after a while 'Disk not ejected properly' pops up, and the only way to get it working again is to restart the computer.
Amazon have exchanged it, but the new one does the same thing.
Thanks in advance.
MDS

 

[Ijack]

Is your Mac going to sleep in the interim? This can cause a problem with some external drives.

There's a fairly long thread on the subject here which has some suggestions worth looking at: https://discussions.apple.com/thread/5496841?start=0&tstart=0

 

[exasperation]

I'm not sure if it goes to sleep in the interim, but I shall keep an eye on it from now on and we'll see.
In the meantime I'll have a look at the thread you suggest.
Many thanks for your help.