Hey JimH, thanks for your quick response.
What do you mean by test them onto a local drive? Do you mean to copy a load of my flac files onto my main drive used by mac os? I could try that and see what hapoens and report back. Leave that with me.
n the meantime, one correction to my post above, it seems that if i change the usb hard drive to the one used by my windows laptop, and make the appropriate rule in portable library, this seems to have the system working for now. Not sure what will happen long term in the days to come but lets see how that goes.
I am running chkdsk on the usb drive used for the mac. If this is culrpit then I could try and use this drive on the laptop and see if I get any issues.
Regarding formatting of this 5TB drive, should it be formatted as ntfs or the mac formating? Should i just wipe this drive and format it on the Mac from scratch and then copy all the files across onto it?