Try a different usb port and also switch I/O to wnaspi32 If still the same research the chipset in your enclosure and buy a different enclosure with a different chipset you may also have to buy another writer, or if you have another writer try that with the enclosure you have at the minute as usb chipset mainboard > I/o > usb chipset enclosure > writer chipset are not getting on so change the combination of these eg new writer in the enc you have may cure, it is very hit and miss but your chances increase the more writers you own versus the more enclosures you have (the weak link will be the mainboard if thats constant and the occurrence of STO keeps happening)