The first gen v4.x single bay/single drive My Cloud Safepoint feature (and Backup feature on v2.x single bay My Cloud devices) is what it is. Like it or not the Safepoint feature can fail to create or copy files to the attached USB hard drive. Most times it works but in rare cases it just doesn’t. The few times a Safepoint failed was due to either files in use or issues with the USB hard drive itself.
For what ever reason the My Cloud can be very picky on working properly with USB hard drives. Personally I found that I had to ensure my USB hard drive had one single partion filling the entire drive and that it was formatted for NTFS.
There are past discussions on issues with Safepoint and workarounds to the issue. I used the Rsync option detailed in the two following discussions for several years rather than Safepoint.
There is also the GoodSync option that might work depending on one’s needs and settings.
https://community.wd.com/search?q=goodsync%20category%3A105
One also has the option of just using third party software to copy the My Cloud user files to a local USB drive or hard drive on the local computer as a secondary backup method. Personally I use freefilesync to copy my data files from a My Cloud to a USB hard drive as a secondary backup method in addition to the rsync script that backs up the My Cloud to a USB hard drive attached to teh My Cloud.
