Why is VSCode "Unable to open Extension. An unknown error occurred."?

Question

This is my first time installing and using VSCode, and when I tried installing Prettier extension, it let me peek quickly at the extension page before closing it and displaying this notification (Screenshot attached):

Unable to open 'Extension: Prettier - Code formatter': An unknown error occurred. Please consult the log for more details..

VSCode screenshot: Notification at bottom right

It's doing this with all other extensions. Searched for a solution but found nothing applicable. Why is this happening and how to fix it?

You might use VSCode's developer console to learn more about the issue, https://stackoverflow.com/questions/30765782/the-use-of-developer-tools-in-vs-code However, I do suggest you open an issue with its vendor, https://github.com/prettier/prettier-vscode/issues who should have better knowledge on what might be wrong. — Lex Li, Apr 13 '20 at 16:32
Have a look at https://stackoverflow.com/questions/61172590/extension-host-unexpectedly-teminated-vscode possibly related. — Mark, Apr 13 '20 at 16:34

score 36 · Accepted Answer · edited Sep 26 '20 at 11:36

36

It happens that, this is a problem with the Egyptian ISPs' default DNS servers, which are most probably blocking some of Microsoft servers.

The solution (in case you live in Egypt):

clear DNS cache using ipconfig /flushdns command on Windows cmd (For Other OS).
change the default DNS servers in your router settings to Google's 8.8.8.8 & 8.8.4.4 (or Cloudflare's 1.1.1.1 or any other DNS server you trust).
restart VSCode and try installing extensions.

Hopefully, everything will work fine by now.

Check this Github issue for more insight.

edited Sep 26 '20 at 11:36

Noha Salah

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answered May 19 '20 at 23:14

Seif A.

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This is how to configure Windows 10 to set DNS: https://www.windowscentral.com/how-change-your-pcs-dns-settings-windows-10 – Ahmed Hammad Jun 21 '20 at 10:09
In my case, you don't need to proceed to step 2 onward. I flushed the DNS and it worked (Windows 10) – Bonifacius Sarumpaet Jan 11 '22 at 14:57
If you cannot/don't want to edit DNS settings, you can open code with the `--ignore-certificate-errors`, install the extensions you need, then restart without the flag. – Lewy Blue Aug 15 '22 at 05:35

Bravo Yeung · Answer 2 · 2020-09-16T10:03:36.187

7

It probably is because of the certificate check.

Below solution works for me in CentOS 7 (Linux).

Step 1. Change the file /usr/share/applications/code.desktop

Open the file /usr/share/applications/code.desktop, then modify the Exec value with adding --ignore-certificate-errors before %F:

Exec=/usr/share/code/code --unity-launch --ignore-certificate-errors %F

Save the file with typing sudo in the begining.

Step 2. Close all windows of vs code instances.

Step 3. Back to the terminal, use below command to open VS code:

code --ignore-certificate-errors

Step 4. Click extension button in the left side bar.

Click any extension like "Ruby" by Peng Lv, if the images in the Details page can be seen successfully, perhaps the issue is solved.

Step 5. Try to continue to install the extensions you need.

Just enjoy! May it be helpful for you.

edited Sep 16 '20 at 10:03

answered Sep 16 '20 at 09:51

Bravo Yeung

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Thank you so much! I use VSCode behind the company proxy and I got XHR error when I tried to download extensions. This solution fixes the problem. – Gobinath May 12 '21 at 20:37
I'm using ubuntu and /usr/share/applications does not exist. Can you tell me where it is in ubuntu? – user2049142 Apr 06 '22 at 20:04
I tried various things, and only this worked. TY! – Terry Sep 13 '22 at 16:50
@Terry So happy it works for you. – Bravo Yeung Sep 14 '22 at 01:07

mohamed elshazly · Answer 3 · 2020-05-28T10:01:14.717

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in ubuntu go to settings -> wifi -> click on gear icon -> IP4 -> dns input and put

8.8.8.8,8.8.4.4

and click apply, to DNS Resolver Cache open terminal and type:-

sudo systemd-resolve --flush-caches
sudo systemctl restart systemd-resolved

restart your device

edited May 28 '20 at 10:01

answered May 27 '20 at 13:36

mohamed elshazly

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score 4 · Answer 4 · answered Nov 12 '21 at 12:52

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For windows

    cd "C:\Users\<user>\Appdata\Local\Programs\Microsoft VS Code"
    code.exe --ignore-certificate-errors

answered Nov 12 '21 at 12:52

linzwelch

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This works for me except I can use `code.cmd` instead of `code.exe` and it's on the path so I don't need to change directory. – Lewy Blue Aug 15 '22 at 05:27

score 3 · Answer 5 · edited Sep 29 '20 at 14:19

The solution

clear DNS cache using command on Windows cmd: ipconfig /flushdns
change the default DNS servers in your router settings to Google's:

8.8.8.8 , 8.8.4.4 >> for IPv4

2001:4860:4860::8888 , 2001:4860:4860::8844 >> for IPv6

This link will guide you how to change the DNS server in windows and mac: https://www.ionos.com/digitalguide/server/configuration/how-to-change-dns-server/
restart VSCode and try installing extensions.

score 2 · Answer 6 · answered Sep 17 '20 at 04:07

2

If you're in a corporate network and it's locked down the one last resort is to manually download the VSIX from the website on a domain that will allow it and then copy over the VSIX and install it.

answered Sep 17 '20 at 04:07

Jeremy Thompson

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Mimina · Answer 7 · 2020-07-21T10:43:06.397

I got this "XHR failed" error in Visual Studio Code.

So I changed my network settings to use Google Public DNS (instructions)

Finally following instructions (by mohamed-mokhtar) solved for me:

Go to : Control Panel\Network and Internet\Network Connections
Choose your connection network and ( right click on it then choose properties )
Select " Internet Protocol Version 4 (TCP/IPv4) and then click on properties in the bottom of this section
At General section click on " Use the following DNS Server address : "
Make " Preferred DNS server : 8.8.8.8 " (if you face a problem check this)
Make " Alternate DNS server : 8.8.4.4 "
Restart VS code

Eslam Magdy · Answer 8 · 2020-08-26T14:58:20.337

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referring to @Seif A. answer

The solution (in case you live in Egypt)

clear DNS cache using command on Windows cmd:

ipconfig /flushdns

change the default DNS servers in your router settings to Google's:

8.8.8.8 , 8.8.4.4  >> for IPv4
2001:4860:4860::8888 , 2001:4860:4860::8844  >> for IPv6

restart VSCode and try installing extensions.

edited Aug 26 '20 at 14:58

answered Aug 26 '20 at 07:14

Eslam Magdy

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@MuhammedMoussa yes, I mentioned that it is for windows CMD – Eslam Magdy Oct 07 '20 at 21:17

score 1 · Answer 9 · answered Sep 22 '20 at 09:05

1

I faced the same problem while adding new extension in vs code. I Recognized the problem within the ISP in Egypt, so I changed the DNS in My router to Google DNS Providers , and it works perfectly

answered Sep 22 '20 at 09:05

A Hagrasi

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score 0 · Answer 10 · answered Sep 17 '20 at 16:51

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Just install a VPN like betternet or any other VPN software and change the country to the USA or try other countries.

answered Sep 17 '20 at 16:51

Abdelrahman Tareq

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score -1 · Answer 11 · answered Sep 01 '21 at 10:42

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In my case I was need to disable work VPN to download extension

answered Sep 01 '21 at 10:42

chill appreciator

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Why is VSCode "Unable to open Extension. An unknown error occurred."?

11 Answers11

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