My My Cloud storage has died, everything still on the cloud, if I upgrade to My Cloud Home can I still access the My Cloud data?
First the My Cloud Home may not be an “upgrade” to the My Cloud. It is a different device with a different set of (possibly fewer) features and options than the My Cloud line. Make sure to read the My Cloud Home subforum to see the many complaints/issues with that product, and visit the My Cloud Home Support page to review that product’s features/options very carefully to ensure they meet your needs.
If you can no longer access your existing My Cloud then you may (probably will) need to disassemble the existing My Cloud enclosure to get at the existing My Cloud hard drive. Once you have access to the existing My Cloud hard drive one can then attach that hard drive to a computer running a Linux OS, or third party Linux drivers for Windows to copy the user files/user data that is typically stored on partition number 4 (sda4) to another location or hard drive.
If you have been performing a My Cloud Safepoint / Backup to a USB hard drive attached to the My Cloud then the latest Safepoint/Backup data should be accessible on that USB drive to be copied to another location.
If the My Cloud hard drive is completely dead (mechanical failure) then one could attempt data recovery using a data recovery service or third party software. Just note that those recovery services tend to be very expensive and result in mixed data recovery results.