Kirk,
Continuing on from this...
I initially viewed the photos on disc inside PM. I then went through and colour marked the photos I wanted to work on. I then viewed the photos that were coloured only and tried to drag them across into a folder for editing. PM would not let this happen. I then removed the colour marking and instead tagged the photos I wanted to edit. Still PM would not allow me to drag the images over. This worked perfectly during the trial. I then tried the copy/move command but PM returned an error.
I then after many times trying downloaded an archive version of PM to see if it would work. This time when I viewed the card the images I had previously selected, then deselected, colour marked and then removed the colour mark were not showing up in the viewing window. All I could see in the space where the images were supposed to be was a grey square/rectangle with the file name underneath, but no image.
I then tried to get the photos using Adobe Bridge however the images I had originally tagged etc in PM were not showing up either.
I then used Finder to view the contents of the card. This showed the files but again the ones I had originally tagged, colour marked in PM were not showing as thumbnails and were infact showing as having been corrupted and would NOT open.
The only way I have been able to recover the images is by using Rescue Disc Pro from Sandisk.
This is extremely worrying as the images here (over 300) were from a 4 hour studio shoot; client fashion/commercial shoot and at this stage I am now very apprehensive about using PM if it is going to seemingly corrupt my files.
I would really appreciate an idea of what is going on here as before PM worked perfectly during the trial period with the same cards. Incidentally I have tried this with other cards too and the same problems occurs.