wavs go offline?

current bug thats been plagueing me for a few versions... example-i have a vocal track that i put a split in and nudge.as soon as i step back or undo the wav is greyed out with "offline".cant redo,have to then tell reaper where the file is but this doesnt work all the time.tried to get in a mantra of manual saving everytime but when you are in the flow its easy to forget.. running latest version of reaper,all files are on a usb3 external-using el capitan(but got the same prob on yosemite) Any hints?

I think it might be just an option,in the media section

cheers, but it isnt that.I did have that ticked but of course as soon as you make reaper the active window the wavs come back online again.This is more like reaper goes senile and forgets where the wav is located.

Ah ok,trying moving the file to the main drive,do some editing & see does it still happen,then you'd know if it was the external drive causing the issue

nope not the drive because the session itself is an old one that had been edited numerous times in this manner from the same drive.Tried a few other sessions (newer) and had no problems but this and one other do...annoying but as im nearly finished both projects its just extra motivationg to get them done and dusted!!!!