Macrium Reflect backup sessions very slow - since Window 10 upgrade?

Last full backup on data drive was 4th May. I do full runs on the first Monday of alternate months. It's only in the past week the run time has increased dramatically. Although I call it my data drive it mainly contains lesser used data, day to day data is on the C: SSD drive, and that's continually backed up by Genie Timeline Pro.

You're right, I meant differential not incremental. I have Reflect free so incremental is not an option.

I'll do a full on the data drive in a few minutes and see what happens to a differential in a day or so.

I'm waiting for Monday's scheduled differential backups to occur in the morning. If this runs for about the duration previously experienced I'll be happy. I'll update this thread then.

The only thing that I wonder about is that if it was due to the time for MR to work its way through the ~400GB of data to identify changes since the last Full, then why was the time for the various phases as quick as normal, in particular the "Looking for changes" phase. It was the Saving Partition phase that took all the extra time.

- - - Updated - - -

Time for an update after this morning's differential backups, with some earlier data for comparison:

System (and frequent data) drive (SSD)
12.6.20 - differential: 20GB file created, took 21m 23s
15.6.20 - differential: 21GB file created, took 20m 52s

Data (infrequently used data) drive (WD 2GB Black drive)
12.6.20 - differential: 5GB file, 50m 35s
12.6.20 - full: 366GB file, 1h 22m 49s
15.6.20 - differential: 104MB file, 1m 3s

So it would seem that having run a full backup has cured the issue and it was as "mngerhold" suggested, to do with the time MR took to identify the changes amongst 400GB of data - though I am curious as to why the time spent "Looking for changes" was only a few seconds, it was the Saving Partition that took the extended time.

Be that as it may, I'll keep an eye on the differential times and, if needed, will increase the frequency of full backups.

[Currently copying all my MR files to a Swap disc to pass over to my son at the weekend for off-site storage.]

I don't know enough about what is going on during the 'looking for changes' stage to understand, but a search for that phrase did flag up a Reflect feature called CBT (Changed Block Tracker) - see ANSWERED: V7.2.4228 - looking for changes is slow
I don't seem to have that element (I am on the 'free' edition - shame on me), so perhaps its only on the 'paid for' edition - which do you have? If you have CBT running, then this page might explain how the time to look for changes can vary:
Macrium Changed Block Tracker - KnowledgeBase v7 - Macrium Reflect Knowledgebase - KnowledgeBase v7 - Macrium Reflect Knowledgebase

Perhaps a Windows update resets the action of CBT? Just a guess.

PS I'd say that the system backup is also somewhat slow: a 20-odd GB file (from ~70GB used on C:) taking 20 minutes? My system disk has only about 24GB used, but a full image of 15GB takes only 3m20s including verifying (that's SSD to HDD). Not that I want to give you extra concerns!

I have the Free edition. The Looking for Changes appears in the scrolling log during the backup, it's not time stamped but merely that I've noticed the phase only takes a relatively short time, 20-30 seconds perhaps.

Looking at the comparison of different MR versions Macrium Software | Macrium Reflect Free I can see no mention of CBT.

No matter, having spent all my career (now retired) in the computer business I continue to have a curiosity about such things.

tpriest said:

I have the Free edition. The Looking for Changes appears in the scrolling log during the backup, it's not time stamped but merely that I've noticed the phase only takes a relatively short time, 20-30 seconds perhaps.

I did run a diffl backup to see the LfC message, and also found (as you say) that it doesn't get time-stamped in the log - and the log in the second of those links (showing CBT init) does not match what I see. It may be a feature they have since dropped (link was 2017).

Thanks - but 'Not available in this edition' - serves me right (not that speed is an issue for me).

Thanks guys for all your most helpful hints, tips, suggestions etc. I'm happy now that the problem is now apparantly resolved and that I have a better understanding of how MR (Free edition!) works.

I'll mark it as Solved.

Once again thank you.

Just to say thanks once again, MR continues to behave itself. I've increased slightly the frequency of full backup of the data drive to, hopefully, avoid a similar issue in the future.

In another couple of weeks I'll probably let 2004 install again.