OK, thank you,
Good to hear a plausible explanation for it and better some lost restore points than a defect hard drive. I hope there are no possibilities that you might lose your own data by defragmentation.
Regrattably no SSD, but a normal 2,5'' SATA (or so).
Defraggler I am using at the moment shows 33 % defragmantation, done in about 3, 4 days, so that means, it will need about a week or so for the rest, I guess. Extremely long time for a partition with 878 GB of two on a 1 TB drive. I assume all of the defrag programs will need about the same time.
Many thanks again.