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Question
Sunday, September 6, 2015 6:21 AM
Hi there
As the title suggests, I am experiencing an issue where full encryption on a data disk is taking much longer on Windows 10 than Windows 8.
Originally on a Windows 8 instance, I set up full drive encryption for both the OS (boot) disk which is an SSD which was fairly quick and painless. I also set up full encryption on a 3TB data disk which understandably took longer as it was a regular 7200 RPM SATA disk, however it did complete in a perfectly reasonable amount of time equating to roughly 10 to 12 hours.
Before performing a clean reinstalling of the system with Windows 10, I turned off BitLocker for both disks which took about the same amount of time to decrypt as it took to encrypt each which is great.
I then formatted and reinstalled the SSD with Windows 10 after which I enabled full drive encryption for it again which as before, completed in a very reasonable amount of time which is all good.
The issue I am experiencing is that when I initiated a full drive encryption on the 3TB data disk, it has been taking significantly longer to encrypt. Its not stuck thankfully, though the encryption process is much slower than before. It only encrypted about 20% in the time it took to previously encrypt as well decrypt (10 to 12 hours each respectively) while running on the previous Windows 8 instance.
At this given rate, it may take several days to finish and I am worried power interruptions (a norm in my country) may disrupt this process. Thankfully I have made backups of both drives beforehand if things really turn out for the worst.
Any ideas why this is taking so long and what can be done to speed it up? Many thanks.
Regards,
CTV
All replies (8)
Wednesday, September 9, 2015 2:38 AM âś…Answered
Hi CTV,
Though the hardware conditions are the same, there is a difference between them. To make a device work well, we also should get a compatible driver.
Have you checked the device manufacturer website to get a Windows 10 compatible driver for the hard drive?
This is the only possible reason I could figure out.
However, we could try the "Encrypt used disk space only" option.
Here is a link including the test result between "full encryption time" and "Used Disk Space Only encryption". You may be interested in.
Try it out: encrypt used space only (Should be applied to Windows 10)
https://technet.microsoft.com/en-us/windows/jj983729.aspx
Fortunately, we needn`t worry about the power interruptions during the long encryption process.
Best regards
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Monday, September 7, 2015 8:30 AM
Hi CTV,
The encryption times vary depending on the type of drive that is being encrypted, the size of the drive, and the speed of the drive.
To speed up the encryption, we could choose the "Encrypt used disk space only" option and keep the machine up to date, download the Windows 10 compatible driver for the device. We could try to divide whole drive into several partitions and encrypt the specific partition one time.
As for the power interruptions, there is no need to worry about this. The BitLocker encryption and decryption process will resume where it stopped the next time Windows starts. This is true even if the power is suddenly unavailable.
Here is a link for reference(Applied to Windows 10):
BitLocker Drive Encryption in Windows 7: Frequently Asked Questions(What happens if the computer is turned off during encryption or decryption?)
https://technet.microsoft.com/en-us/library/ee449438(WS.10).aspx
Best regards
Please remember to mark the replies as answers if they help, and unmark the answers if they provide no help. If you have feedback for TechNet Support, contact [email protected].
Monday, September 7, 2015 8:50 AM
Hi CTV,
The encryption times vary depending on the type of drive that is being encrypted, the size of the drive, and the speed of the drive.
To speed up the encryption, we could choose the "Encrypt used disk space only" option and keep the machine up to date, download the Windows 10 compatible driver for the device. We could try to divide whole drive into several partitions and encrypt the specific partition one time.As for the power interruptions, there is no need to worry about this. The BitLocker encryption and decryption process will resume where it stopped the next time Windows starts. This is true even if the power is suddenly unavailable.
Here is a link for reference(Applied to Windows 10):
BitLocker Drive Encryption in Windows 7: Frequently Asked Questions(What happens if the computer is turned off during encryption or decryption?)
https://technet.microsoft.com/en-us/library/ee449438(WS.10).aspxBest regards
Please remember to mark the replies as answers if they help, and unmark the answers if they provide no help. If you have feedback for TechNet Support, contact [email protected].
Thank you for your response. I understand that there are variables that can affect the encryption time, however I did mention that this is the exact same system and configuration, the only difference is that it was running Windows 8 before which took 10-12 hours to perform a full disk encryption for the 3 TB drive, yet the Windows 10 instance on the exact same system with the exact same hardware at the given rate may take up to 2-2.5 days to complete full disk encryption on the exact same disk which on Windows 8 took 10-12 hours before.
Saturday, November 21, 2015 1:54 PM
The new encryption that comes with version 1511 take even longer. With the 256 bit option for full disk encryption it take 24 hours on a 1 TB WD blue. The bottleneck is the hard drive. Its a lot faster on an SSD.
Monday, January 4, 2016 7:23 PM
I also suffer from this same problem on both Windows 10 builds, there is certainly some bug in the encryption process as i have done the exact same encryption on the exact same hardware since windows 7, 8, 8.1 and 10, and i have only noticed that windows 10 dramatically takes longer to encrypt, even on an SSD in comparison to previous Windows versions.
This is a bug I am sure. trying to perform upgrades in the business to Windows 10 and enabling encryption is a nightmare as it's an overnight job. not only is the encryption process drastically slower but also system performance is hindered massively during encryption, where as previous versions of windows were very very functional during encryption. we simply can't use the system at all while it encrypts on Windows 10. The only way in our company to improve this is to enable encryption on Windows 8.1, perform the upgrade and then it doesnt need re-encrypting, Windows 7 users are stuck though as we dont have bitlocker on our Windows 7 Pro licenses.
Thursday, June 16, 2016 11:55 AM
TL;DR:
To get a 5x speed boost on encrypting your full drive in Windows 10:
1. Enable Bitlocker in the running OS, but pause the encryption once it's in progress
2. Create a recovery disk, boot it up, go to command line
3. Resume encryption of the drive using "manage-bde -resume" while in the recovery environment
(4. Pause again at 99% and go back to the running OS and finish it from there...? This is probably unnecessary, but this is what I did.)
==========
I just tried to encrypt my 2TB external HDD on the latest Windows 10 Pro using Bitlocker (entire drive, compatible mode), and since I only got to 3% within ~2 hours, I started looking into what was going on. I checked on Task Manager's Performance tab, and while CPU and memory was idling, disk usage on the affected drive was at 100% constantly. However, at the same time, it reported 10 MB/s read and also 10 MB/s write, which was very slow compared to how this drive performs when I read / write files myself. This is when I started searching the internet and found this thread.
First I wanted to obtain a Windows 8.1 Recovery Disk, to try to boot it up and encrypt the drive from the command line tool "manage-bde", hoping that it would be a lot faster as reported here. However, I wasn't able to find an ISO for that recovery disk, so I gave up on that. But as a last effort, I decided to try the same with the Windows 10 Recovery Disk that I could simply create from my running OS. And the trick worked!
Windows 10 Pro (same machine, same drive, same everything!), Running OS vs. Recovery Disk
(I will just post the results in "percent per hour", as it shows the speedup just fine, but if you'd like, you can calculate MB/s.)
=== Encryption phase 1 - Running OS ===
20:13 - 0.0%
00:01 - 5.9% --> 1.553% per hour
=== Encryption phase 2 - Recovery Disk ===
00:08 - 5.9%
00:39 - 11.0% --> 9.871% per hour
02:07 - 25.3% --> 9.750% per hour
04:44 - 50.0% --> 9.439% per hour
11:41 - 99.2% --> 7.079% per hour
=== Encryption phase 3 - Running OS ===
12:10 - 99.2%
12:41 - 100.0% --> 1.548% per hour
=== Results ===
Running OS: average 1.55% per hour; estimated total 64.5 hours
Recovery Disk: average 8.08% per hour; estimated total 12.4 hours
SPEED UP: ~5x
My guess is that Windows 10 is throttling the encryption process to a "safe speed" for some reason, probably to keep the system usable while it's working. You can see that the processing speed is approximately the same at the start (~0%) and at the end (~100%) when the OS is running, whereas it gradually slows as we get to the slower parts of the disk while encrypting in the recovery environment. So basically the disk IO is really maxed out in the recovery environment, while the bottleneck is somewhere else in the running OS.
Tuesday, June 21, 2016 6:06 PM
looks like your analysis is pretty good, i haven't tested this myself yet, but it seems rational. however i dont agree with the last paragraph in terms of throttling the bitlocker to make the system usable, this is actually part of the problem i have faced - the OS isnt usable while it's doing bitlocker encryption, yet active time is 100% and i'm seeing similar throughput of 5-10MB/s on the disk, when top speed should be around 150-175MB/s for what the disk can perform.
Given that a lot of people won't know how to use the recovery environment but will barely understand how to encrypt the disk, this workaround is only really appropriate for IT Pros, and waiting 65 hours for a 2TB drive to encrypt is ridiculous, on Windows 7/8/8.1 it took less than 24 hours (i think around 17-19) for my USB 2.0 1TB drive to encrypt and that uses IDE disks 10 years old now, throughput of around 20-25MB/s if it were 2 TB that still beats your modern day SATA on modern Windows 10. it's a bug for sure and it would be great for MS to acknowledge that and fix it. we simply can't encrypt our systems during an upgrade for users unless we run it overnight, even then we have had a handful of users complain about unusable systems until the late morning/lunch time the next day because it's still finishing off encryption!
thanks for your post though, i may well give this a go when i next have to encrypt a large disk.
Thursday, September 8, 2016 1:51 PM
Lads , i'm also having problems with bit locker, impressive how long it takes to finish, what i notice its that the most recent laptops have raid on option on sata config ( bios ) and these guys at least finish the process in about 6 hours. the ones i'm running now the bit locker are only AHCI and ATA, there is tests for speed and proves that ATA its lower speed reading but faster speed writing then AHCI, i know sounds not good ideia but what im trying now its basicly use ATA cuz the process never finish man, been left already for 2 days running and nothing . btw there is just windows 10 and some basicly apps on the HD , recently formatted .
cheers