My Toshiba Satellite p50-c-18k has an SSD of only 250 GB and was running out of space. I've bought a new SSD of twice the capacity and, using Acronis 2020, I've copied the first to the second (three times now), but the computer won't recognize it. The copying process is supposed to leave the SSD in GPT format (because I don't think the Toshiba can read MBR format) but right at the end of the process, a message appears referring to MBR , and then there's one which says something like "synchronising with the operating system". I've seen several suggested solutions. One was to make a Windows 10 Recovery USB but this again is not recognized by the computer. Anything on memory sticks or DVDs has to be in MBR format (or so I understand), and in the "BIOS" of my computer, UEFI is greyed and seems to be the only interface option. Can anyone suggest a solution? Many thanks.