Solved Why is openssh an optional feature and takes ages to install (add optional feature)

jimbo45 · Jun 21, 2025

Hi folks

many people want to simply ssh into windows from remote clients -- but this needs openssh to be up and running on the target machine. It can be added via add optional feature but that takes ages (goodness knows why) and you have to enable the openssh server to start automatically in services after installing the feature.

On a fast machine it's taken 9 minutes to get to this point -- nothing else running !!!!

What's even more bonkers it's the sme problem with Windows 2025 LTSC server -- you'd think a server should surely have this enabled in its core features !!!.

Cheers
jimbo

garlin · Jun 21, 2025

Why the delay? OpenSSH is an optional FOD package which isn't integrated in the install image. If it was already on-disk, DISM /Add-Capability would only take a minute or two. MS could bundle OpenSSH, but half of you folks would loudly complain Windows is too bloated.

Downloading the 2-3 MB OpenSSH feature doesn't take that long. But since it's not an on-disk feature, Windows has to first install the package and re-apply the current Monthly Update on top of it (in case the same feature was patched by the CU). This takes the bulk of your time waiting.

The Windows servicing model always delivers the same base FOD package, you can't get a Dec 2024 or May 2025 updated version. So the CU must always be checked and applied over it to bring the FOD up to date. Not to mention any installed Language Packs. That's why you're sitting there for 10 min. to install a 2-3 MB feature.

PS - 24H2 CU does patch the OpenSSH files...

hsehestedt · Jun 21, 2025

Wow, I would have never guessed that. Fantastic info, garlin.

garlin · Jun 21, 2025

Same reason Language Packs take forever to install on a live system. Windows Settings is secretly re-applying the CU, because patches have to be applied in order (base package first, update last). Otherwise you will have an inconsistent install image.

When you do DISM updates to an offline image, doing it in the correct order is YOUR PROBLEM. And a common mistake is to apply LP's after the CU. Otherwise you get the common problem of "I get the wrong translations".

hsehestedt · Jun 21, 2025

I'm guessing it must be the same for the old .NET. Two days I installed it on an old machine that needs it for its hotkey utility. It took about 15 minutes to install.

jimbo45 · Jun 22, 2025

garlin said:
Why the delay? OpenSSH is an optional FOD package which isn't integrated in the install image. If it was already on-disk, DISM /Add-Capability would only take a minute or two. MS could bundle OpenSSH, but half of you folks would loudly complain Windows is too bloated.

Downloading the 2-3 MB OpenSSH feature doesn't take that long. But since it's not an on-disk feature, Windows has to first install the package and re-apply the current Monthly Update on top of it (in case the same feature was patched by the CU). This takes the bulk of your time waiting.

The Windows servicing model always delivers the same base FOD package, you can't get a Dec 2024 or May 2025 updated version. So the CU must always be checked and applied over it to bring the FOD up to date. Not to mention any installed Language Packs. That's why you're sitting there for 10 min. to install a 2-3 MB feature.

PS - 24H2 CU does patch the OpenSSH files...

Thanks -- it's great to get info --- intuitively you can see why a small package makes one wonder why it takes that long to install it. The same thing happens if you add things like the extra pan european fonts / chinese / hebrew etc.

Cheers
jimbo

mfessler · Oct 7, 2025

garlin said:
Same reason Language Packs take forever to install on a live system. Windows Settings is secretly re-applying the CU, because patches have to be applied in order (base package first, update last). Otherwise you will have an inconsistent install image.

Please excuse me for hijacking the thread.
Are you sure that when installing language packs via the GUI (on a live system), the LCU is automatically reinstalled?
The following is often quoted:

After you install a language pack, you have to reinstall the latest cumulative update (LCU).
If you do not reinstall the LCU, you may encounter errors.
If the LCU is already installed, Windows Update does not offer it again. You have to manually install the LCU.
Source

So, does this only apply to an offline image?

Thanks and all the best, Martin

garlin · Oct 7, 2025

When you add LP's to an offline image, the LP update packages must be processed first (and alone). Then you can reload the image and apply any LCU's. There's a specific ordering of how the component folders are supposed to "stack" like a cake with different layers.

[top]
LCU
Language Packs
base Windows
[bottom]

This order can causes problems with incorrectly translated text:
[top]
Language Packs
LCU
base Windows
[bottom]

When you add LP's (or some Optional Features) through the Settings app, it's doing behind-the-scenes magic to to re-apply any updates back on top of the newly installed LP's. This is why it takes forever to process.

spapakons · Oct 10, 2025

That explains why it takes too long to add optional features. Also why adding language packs sometimes displays mixed text and is fixed later when installing new updates. Thanks for the info! However, it is a little weird. When you choose more than one optional feature, it should install them all and then install the LCU once and for all. I guess it installs it every single time to avoid system issues if the computer suddenly restarts or something before the LCU is installed.

SlicEnDicE · Oct 10, 2025

jimbo45 said:
On a fast machine it's taken 9 minutes to get to this point -- nothing else running !!!!

That is twice as long compared to what it took for my phone to downoad latest Android OS update (4.2GB), apply the update, reboot, enter SIM and lockscreen credentials and be up and running again.

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