Solved Macrium Reflect: Strange Differential Backup sizes


Peter B

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I'm using the Home Version 8.0.6867 and I always perform a full back every Sunday, with daily scheduled differentials for the remainder of the week.

Occasionally, one of the differential backup sizes increases to a disproportionate figure - see the attached image from Sunday through today - when there has been hardly any usage on my laptop. No Windows updates, no programs added or deleted etc.

I just wondered if anyone could shed some light on it, please?
 

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My Computer

System One

  • OS
    Windows 11 Pro 23H2 22631.3880
    Computer type
    Laptop
    Manufacturer/Model
    PC Specialist Initia 15.6"
    CPU
    Intel(R) Core(TM) i7-1195G7 @ 2.90GHz
    Memory
    16GB
    Graphics Card(s)
    Intel Iris Xe
    Screen Resolution
    1920 x 1080
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    M2 PCIe NVMe 250GB
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    80/20 Mbps
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    Microsoft Edge Version 126.0.2592.113 (Official build) (64-bit)
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    Macrium Reflect Home Edition v8.1.8110
This explains it (?) From macrium help:

ifferential Images​

A differential image stores the changes that have been made to the imaged file system since the last full image. Subsequent differentials can be taken, but only one differential and the full are required in order to fully restore the system.
This is quicker than creating a full image, however the longer the time between the full and the differential, the larger the differential image file is and the longer it takes to create.

Advantages of differential images:

  • Differential images created after the initial full Image are very quick because only file system changes since the full backup are saved.
  • The amount of disk space used by differential images is significantly less than that of full images.
  • Only two image files are required to restore the system.
Disadvantages of differential images:

  • As the time since the last full image was taken increases, the size of the differential grows as does the time it takes to create the differential image.
  • In order to reduce this time, it is necessary to perform a full image occasionally to reduce the size of the subsequent differential images.
 

My Computer

System One

  • OS
    Windows 10/11
Hi Davehc. I have seen that 'explanation' on their website, but a 5GB difference in one day doesn't make sense, does it? Especially when I hardly used my machine at all yesterday...
 

My Computer

System One

  • OS
    Windows 11 Pro 23H2 22631.3880
    Computer type
    Laptop
    Manufacturer/Model
    PC Specialist Initia 15.6"
    CPU
    Intel(R) Core(TM) i7-1195G7 @ 2.90GHz
    Memory
    16GB
    Graphics Card(s)
    Intel Iris Xe
    Screen Resolution
    1920 x 1080
    Hard Drives
    M2 PCIe NVMe 250GB
    Internet Speed
    80/20 Mbps
    Browser
    Microsoft Edge Version 126.0.2592.113 (Official build) (64-bit)
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    Microsoft Defender
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    Macrium Reflect Home Edition v8.1.8110
Occasionally, one of the differential backup sizes increases to a disproportionate figure - see the attached image from Sunday through today - when there has been hardly any usage on my laptop. No Windows updates, no programs added or deleted etc.

I just wondered if anyone could shed some light on it, please?
Each differential has to be larger than the previous one, as it has to include all previous changes since the Full, plus any new ones.

As you have Home you could use Incrementals instead. These only include changes made since the last backup, be that a Full, Differential or Incremental.

In addition, if the partition being backed up has been defragmented since the last backup then the sectors holding the files have changed, even if the files themselves have not. All these changes have to be included in the next Differential/Incremental. On all my machines with HDDs I have turned off scheduled optimisation to avoid this.

This should normally only be an issue if the drive is an HDD, an SSD should not need to be defragmented.
 

My Computers

System One System Two

  • OS
    Windows 11 Home
    Computer type
    Laptop
    Manufacturer/Model
    Acer Aspire 3 A315-23
    CPU
    AMD Athlon Silver 3050U
    Memory
    8GB
    Graphics Card(s)
    Radeon Graphics
    Monitor(s) Displays
    laptop screen
    Screen Resolution
    1366x768 native resolution, up to 2560x1440 with Radeon Virtual Super Resolution
    Hard Drives
    1TB Samsung EVO 870 SSD
    Internet Speed
    50 Mbps
    Browser
    Edge, Firefox
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    Defender
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    fully 'Windows 11 ready' laptop. Windows 10 C: partition migrated from my old unsupported 'main machine' then upgraded to 11. A test migration ran Insider builds for 2 months. When 11 was released on 5th October it was re-imaged back to 10 and was offered the upgrade in Windows Update on 20th October. Windows Update offered the 22H2 Feature Update on 20th September 2022. It got the 23H2 Feature Update on 4th November 2023 through Windows Update.

    My SYSTEM THREE is a Dell Latitude 5410, i7-10610U, 32GB RAM, 512GB NVMe ssd, supported device running Windows 11 Pro (and all my Hyper-V VMs).

    My SYSTEM FOUR is a 2-in-1 convertible Lenovo Yoga 11e 20DA, Celeron N2930, 8GB RAM, 256GB ssd. Unsupported device: currently running Win10 Pro, plus Win11 Pro RTM and Insider Dev, Beta, and RP 24H2 as native boot vhdx.

    My SYSTEM FIVE is a Dell Latitude 3190 2-in-1, Pentium Silver N5030, 4GB RAM, 512GB NVMe ssd, supported device running Windows 11 Pro, plus the Insider Beta, Dev, Canary, and Release Preview builds as a native boot .vhdx.
  • Operating System
    Windows 11 Pro
    Computer type
    Laptop
    Manufacturer/Model
    Dell Lattitude E4310
    CPU
    Intel® Core™ i5-520M
    Motherboard
    0T6M8G
    Memory
    8GB
    Graphics card(s)
    (integrated graphics) Intel HD Graphics
    Screen Resolution
    1366x768
    Hard Drives
    500GB Crucial MX500 SSD
    Browser
    Firefox, Edge
    Antivirus
    Defender
    Other Info
    unsupported machine: Legacy bios, MBR, TPM 1.2, upgraded from W10 to W11 using W10/W11 hybrid install media workaround. In-place upgrade to 22H2 using ISO and a workaround. Feature Update to 23H2 by manually installing the Enablement Package. Also running Insider Beta, Dev, and Canary builds as a native boot .vhdx.

    My SYSTEM THREE is a Dell Latitude 5410, i7-10610U, 32GB RAM, 512GB NVMe ssd, supported device running Windows 11 Pro (and all my Hyper-V VMs).

    My SYSTEM FOUR is a 2-in-1 convertible Lenovo Yoga 11e 20DA, Celeron N2930, 8GB RAM, 256GB ssd. Unsupported device: currently running Win10 Pro, plus Win11 Pro RTM and Insider Dev, Beta, and RP 24H2 as native boot vhdx.

    My SYSTEM FIVE is a Dell Latitude 3190 2-in-1, Pentium Silver N5030, 4GB RAM, 512GB NVMe ssd, supported device running Windows 11 Pro, plus the Insider Beta, Dev, Canary, and Release Preview builds as a native boot .vhdx.
Hi Davehc. I have seen that 'explanation' on their website, but a 5GB difference in one day doesn't make sense, does it? Especially when I hardly used my machine at all yesterday...
5 GB in a day can easily happen e.g. temporary files not yet cleaned up.
 

My Computer

System One

  • OS
    Windows 10 Pro + others in VHDs
    Computer type
    Laptop
    Manufacturer/Model
    ASUS Vivobook 14
    CPU
    I7
    Motherboard
    Yep, Laptop has one.
    Memory
    16 GB
    Graphics Card(s)
    Integrated Intel Iris XE
    Sound Card
    Realtek built in
    Monitor(s) Displays
    N/A
    Screen Resolution
    1920x1080
    Hard Drives
    1 TB Optane NVME SSD, 1 TB NVME SSD
    PSU
    Yep, got one
    Case
    Yep, got one
    Cooling
    Stella Artois
    Keyboard
    Built in
    Mouse
    Bluetooth , wired
    Internet Speed
    72 Mb/s :-(
    Browser
    Edge mostly
    Antivirus
    Defender
    Other Info
    TPM 2.0
Thanks for all your replies, but I'm still convinced there's something not quite right...it only occurs once in a blue moon, however, so it's no big deal.
During a 'normal' week, it always increases accumulatively during the 7 day cycle, but usually by expected amounts - for example, the difference between the previous Sunday through Saturday was only around 2GB in total in 6 days...and during that period, there were Windows and Program updates...
 

My Computer

System One

  • OS
    Windows 11 Pro 23H2 22631.3880
    Computer type
    Laptop
    Manufacturer/Model
    PC Specialist Initia 15.6"
    CPU
    Intel(R) Core(TM) i7-1195G7 @ 2.90GHz
    Memory
    16GB
    Graphics Card(s)
    Intel Iris Xe
    Screen Resolution
    1920 x 1080
    Hard Drives
    M2 PCIe NVMe 250GB
    Internet Speed
    80/20 Mbps
    Browser
    Microsoft Edge Version 126.0.2592.113 (Official build) (64-bit)
    Antivirus
    Microsoft Defender
    Other Info
    Macrium Reflect Home Edition v8.1.8110
Don't be too quick to dismiss what Bree noted. Have you actually checked to see if a Defrag happened between those days? As noted by Bree, this would tend to specifically affect a HDD rather than an SSD. Let me explain how this works and how to check...

So, let's assume that you have a bit of fragmentation and you perform a full backup today. Sometime after that backup a Defrag gets performed. The next day a differential is performed but you have not changed a single file nor have you added any files at all to the system, but you still have a large differential backup. That can be absolutely normal. Remember, Macrium Reflect disk image backups are BLOCK based backups, NOT file based backups. So, if you have a 4Gb file that wasn't altered by you, but it was defragged, any blocks altered by Defrag will have to get backed up. This could result in up to 4Gb of backup even though you never altered a single byte.

I'm not saying for sure that is what happened here, but let's check. In File Explorer, right-click the drive that you are backing up and select Properties. Go to the Tools tab and select Optimize. When was the last time that it was optimized?

If that turns out to be the cause, it's easy to work around. Start by disabling the automatic schedule. Then run a Defrag / optimization after the last differential for the week but before the full backup by using Task Scheduler to perform a Defrag using command line commands. You can run Defrag /? To see the syntax. Since the full backup will backup everything anyway, we don't care if a Defrag changes a lot of blocks before it runs.

Also, be aware that Macrium Reflect image backups are unaffected by changes to temp files such as the page file or hibernation files as the blocks occupied by these are excluded from backups.

So, after all that - if this turns out not to be the cause of the issue let us know and we'll see if we can determine any other cause.
 

My Computers

System One System Two

  • OS
    Win11 Pro 24H2
    Computer type
    PC/Desktop
    Manufacturer/Model
    Kamrui Mini PC, Model CK10
    CPU
    Intel i5-12450H
    Memory
    32GB
    Graphics Card(s)
    No GPU - Built-in Intel Graphics
    Sound Card
    Integrated
    Monitor(s) Displays
    HP Envy 32
    Screen Resolution
    2560 x 1440
    Hard Drives
    1 x 2TB NVMe SSD
    1 x 4TB NVMe SSD
    1 x 4TB 2.5" SSD
    PSU
    120W "Brick"
    Keyboard
    Corsair K70 Mechanical Keyboard
    Mouse
    Logitech MX Master 3
    Internet Speed
    1Gb Up / 1 Gb Down
    Browser
    Edge
    Antivirus
    Windows Defender
  • Operating System
    Win11 Pro 23H2
    Computer type
    Laptop
    Manufacturer/Model
    Lenovo ThinkBook 13x Gen 2
    CPU
    Intel i7-1255U
    Memory
    16 GB
    Graphics card(s)
    Intel Iris Xe Graphics
    Sound Card
    Realtek® ALC3306-CG codec
    Monitor(s) Displays
    13.3-inch IPS Display
    Screen Resolution
    WQXGA (2560 x 1600)
    Hard Drives
    2 TB 4 x 4 NVMe SSD
    PSU
    USB-C / Thunderbolt 4 Power / Charging
    Mouse
    Buttonless Glass Precision Touchpad
    Keyboard
    Backlit, spill resistant keyboard
    Internet Speed
    1Gb Up / 1Gb Down
    Browser
    Edge
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    Windows Defender
    Other Info
    WiFi 6e / Bluetooth 5.1 / Facial Recognition / Fingerprint Sensor / ToF (Time of Flight) Human Presence Sensor
Sorry, I didn't mean to sound dismissive - I hadn't considered the defrag/optimisation effect. My SSD was trimmed at 17.50 yesterday, so that's probably the answer, thank you all.
I'll look at an optimisation schedule, or only perform it prior to a backup.
 

My Computer

System One

  • OS
    Windows 11 Pro 23H2 22631.3880
    Computer type
    Laptop
    Manufacturer/Model
    PC Specialist Initia 15.6"
    CPU
    Intel(R) Core(TM) i7-1195G7 @ 2.90GHz
    Memory
    16GB
    Graphics Card(s)
    Intel Iris Xe
    Screen Resolution
    1920 x 1080
    Hard Drives
    M2 PCIe NVMe 250GB
    Internet Speed
    80/20 Mbps
    Browser
    Microsoft Edge Version 126.0.2592.113 (Official build) (64-bit)
    Antivirus
    Microsoft Defender
    Other Info
    Macrium Reflect Home Edition v8.1.8110
Sorry, I didn't mean to sound dismissive - I hadn't considered the defrag/optimisation effect. My SSD was trimmed at 17.50 yesterday, so that's probably the answer, thank you all.
I'll look at an optimisation schedule, or only perform it prior to a backup.
If you run into any more issues, give a shout back. BTW, I'm sure no one thought you were being dismissive. Sometimes it's just hard to wade through all the available info :-)
 

My Computers

System One System Two

  • OS
    Win11 Pro 24H2
    Computer type
    PC/Desktop
    Manufacturer/Model
    Kamrui Mini PC, Model CK10
    CPU
    Intel i5-12450H
    Memory
    32GB
    Graphics Card(s)
    No GPU - Built-in Intel Graphics
    Sound Card
    Integrated
    Monitor(s) Displays
    HP Envy 32
    Screen Resolution
    2560 x 1440
    Hard Drives
    1 x 2TB NVMe SSD
    1 x 4TB NVMe SSD
    1 x 4TB 2.5" SSD
    PSU
    120W "Brick"
    Keyboard
    Corsair K70 Mechanical Keyboard
    Mouse
    Logitech MX Master 3
    Internet Speed
    1Gb Up / 1 Gb Down
    Browser
    Edge
    Antivirus
    Windows Defender
  • Operating System
    Win11 Pro 23H2
    Computer type
    Laptop
    Manufacturer/Model
    Lenovo ThinkBook 13x Gen 2
    CPU
    Intel i7-1255U
    Memory
    16 GB
    Graphics card(s)
    Intel Iris Xe Graphics
    Sound Card
    Realtek® ALC3306-CG codec
    Monitor(s) Displays
    13.3-inch IPS Display
    Screen Resolution
    WQXGA (2560 x 1600)
    Hard Drives
    2 TB 4 x 4 NVMe SSD
    PSU
    USB-C / Thunderbolt 4 Power / Charging
    Mouse
    Buttonless Glass Precision Touchpad
    Keyboard
    Backlit, spill resistant keyboard
    Internet Speed
    1Gb Up / 1Gb Down
    Browser
    Edge
    Antivirus
    Windows Defender
    Other Info
    WiFi 6e / Bluetooth 5.1 / Facial Recognition / Fingerprint Sensor / ToF (Time of Flight) Human Presence Sensor

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