I am very dissappointed in version 7. Very often the backup fails without a clear reason. I am thinking about returning to version 6 where I never had those problems. I have had to start all over again several times with the backup definition files. Then it goes well a few times. But not very long though, I dont know why Macrium release such a bad update.

Can you post log files for some of your failed backups and describe your backup strategy (e.g. schedule type, destination, etc.)? What prompted all of those times you "started all over again" with the backup definition files and what if anything changed after you did that?  Have you created any other threads here or reached out to Macrium Support about V7 issues until now?  Can you confirm you're on the latest update for V7?  If you came here hoping for help, you're going to need to provide more information.  Or if your mind is made up on going back to V6, the latest build of V6 accepts V7 license keys, so other than needing to un-license your V7 installation and recreate your schedule entries (and maybe start new Full backup chains?), that shouldn't be too difficult.

The only benefit I gained from upgrading 2 machines to v7 is slower backups.  Not worth the money.

Are you on the latest update too? A few users noticed this and it was often due to Reflect switching from defaulting to direct I/O to using the file system buffer, which was good for some and not for others. Then in an update early this month added an auto-detect function to test each method once per drive and stick to whichever is faster. In either case the problem has seemed to be third-party antivirus interfering with Reflect -- some get in the way of direct I/O and others get in the way of the file system buffer method, which is just one more on a long list of reasons I think using third-party AV is a mistake. Then verify speed was improved in a very recent update according to the release notes if you're using that, and the very latest release from a few days ago resolves an issue some people were seeing involving extremely slow transfer rates on disk image backups.

Yes, in fact my weekly fulls are running now.  I will check again once these are done.  Last week I saw no improvements.  Win10 Creators Update with all backups going to local QNAP NAS.