Thanks for your reply. Yes it works but does it really work? Are you using your portable recuva in the same way as me? If I put my USB memory stick into a working computer and double click on recuva64.exe in File Explorer then it works as normal. It also works if I run it from the command prompt. But if I boot from the USB stick, which also contains the Windows 10 recovery programs, then recuva has the problem I described. Have you ever done that? I'd be interested to hear if you have done that without any problems and, if so, I'd appreciate it if you could offer any tips. I'd just like to know how your USB drive could be different to mine. Several people have had this problem here and probably a lot more that we don't know about. I don't think putting recuva onto a USB flash drive along with the Windows 10 recovery programs is an unusual thing to do and so I don't know why recuva wouldn't work in that situation.
Thanks.