VSCode Remote Server Connection Issue

Question

Hi,

I have an issue with my logging into a remote server on VSCode. It was all fine until last Friday, but on Sartuday, I could not log into the remote server even though I typed in the correct password. After I typed in the password, it said "Opening Remote Server..." at the bottom left corner, and a "Downloading VSCode Server..." message pops up; however, after a while, it will ask me to enter the password again. So, I checked on the pc terminal, but I can connect to remote server fine, and my password is correct. I went to piazza (Q&A community), and there were around two people who had the same issue as me, and they said that their disk quota was full, and that's why they couldn't login, but if you check the image I attached below, it is not full at all. (But, I still deleted some just in case.) I have a CS student, and I have programming assignment (pair project), labs and final coming up, so I really need this to be fixed, and there were also suggestions that I should try reinstalling VSCode, but then now, it shows an error message. I went to the help desk in the CS building today, but it was not helpful either... they said it might be due to plugin update or VSCode configuration issues... (I am not sure if I touched something while I was trying to fix this issue, but I am desperate to be able to login back to the remote.)Thank you so much for your help.

Answer 1

Hello YY_Duck,

I'm Riza an Independent Advisor. Thank you for reaching out to the Microsoft Community. Let's work on resolving your issue together.

For the meantime, I need help with additional information

What is the exact error message you see after reinstalling VSCode? This is the most important piece of information right now. Please provide the full text of the error.

Can you confirm the exact version of VSCode you are running on your local machine? (Help > About VS Code)

Can you confirm the operating system of your local machine and the remote server? (e.g., Windows 10, macOS Ventura, Ubuntu 22.04 LTS, CentOS 7, etc.)

Are you using the VSCode Remote - SSH extension? (You likely are, but it's good to confirm).

Have you tried connecting to the remote server using SSH from your local terminal (outside of VSCode) since the issue started? You mentioned you checked on the PC terminal and could connect fine, but it's worth re-confirming now to rule out any recent changes to your SSH client or network.

Best Regards,

RizaP

Answer 2

What is the exact error message you see after reinstalling VSCode? 

Version of VSCode:

Operating system and remote server:

Edition Windows 11 Home

Version 24H2

Installed on ‎11/‎02/‎2025

OS build 26100.4351

Experience Windows Feature Experience Pack 1000.26100.107.0

I was using VSCode Remote-SSH extension. (Now it's not connecting, and I am installaed with Remote-SSH extension, but >< icon at left bottom doesn't even show up.... it was showing up before, but after reinstalling VSCode it doesn't show up)

Yes I tried again, and it still shows that I am able to login.

Answer 3

Thank you so much. The error message provides a very clear diagnosis:

The core of the problem is: RangeError: WebAssembly.instantiate(): Out of memory: Cannot allocate Wasm memory for new instance

This indicates that the VSCode server, when trying to launch on your remote machine, is running out of memory. Specifically, it's failing to allocate WebAssembly (Wasm) memory, which is used by Node.js (v22.15.1, as indicated) to run parts of the VSCode server.

Even though your df -h might show plenty of disk space, this is a RAM (Random Access Memory) issue on the remote server.

It seems your local VSCode updated on June 11, 2025, to Version 1.101.0. This is a very recent version. It's possible that this new version of the VSCode server, along with its bundled Node.js v22.15.1, has a higher memory requirement than previous versions, or there's a memory leak/inefficiency on your specific remote server's setup with this new server version.

The fact that the Remote-SSH icon isn't showing up after reinstalling suggests the extension isn't fully initializing or is hitting this server-side error immediately.

Primary Solution: Address Remote Server Memory

Contact your System Administrator/University IT (CS Department Help Desk): This is the most direct and likely solution.

Show them the exact error message (copy and paste it, or show the screenshot).

Explain that the VSCode remote server is failing with an "Out of memory: Cannot allocate Wasm memory" error.

Request an increase in memory allocation for your user process on the remote server, or inquire if there are any per-user memory limits (ulimits) that could be adjusted.

Explain that this started after a recent VSCode update, suggesting the new server version might require more RAM.

Ask if they can check the server's overall memory usage and any per-user resource limits.

Why this is crucial: If the server genuinely doesn't have enough available RAM for your user's processes or if there are strict memory limits imposed on individual users, there's little you can do on your end.

Secondary Troubleshooting Steps (while waiting for IT):

Even though the error points to memory, let's try some things on your end that might help if the memory issue is borderline or if there's a cached process causing issues.

Crucial: Force-Clean the Remote VSCode Server Installation (Again):

Connect to your remote server via SSH from your local terminal.

Ensure VSCode is completely closed on your local machine.

Run these commands:

Bash

cd ~

rm -rf ~/.vscode-server

Optional: Clean the server's cache as well, just in case

rm -rf ~/.vscode-server-insiders # If you ever used insiders build

rm -rf ~/.vscode-server-ipcs # IPC files

Now, try to manually kill any lingering Node.js processes or code-server processes that might still be running and consuming memory.

Bash

ps aux | grep node

ps aux | grep code-server

For each relevant process you find (especially those tied to your user or port), kill it:

kill -9 <PID>

Log out of the remote SSH session.

Restart VSCode on your local machine and try connecting. This will force VSCode to redownload and try to install the server from scratch. If the memory issue is very tight, this might still fail, but it's important to start clean.

Check Remote Server's Available Memory & Ulimits (if you have permission):

SSH into your remote server.

Run free -h to see the overall memory usage on the server.

Run ulimit -a to see your user's current resource limits. Look specifically for max memory size (kbytes) or virtual memory (kbytes). If these are set to a low value, this confirms the memory limit is the issue.

Consider Downgrading VSCode (as a last resort if IT cannot help quickly):

If your university IT cannot immediately increase your memory limits or resolve the issue on the server, a temporary workaround might be to downgrade your local VSCode client to an older version that bundled a less memory-intensive server, or an older Node.js version.

You can find older VSCode .exe or .deb/.rpm files on the official VSCode releases page: https://code.visualstudio.com/updates/v1_xx (replace xx with a version number).

You'd need to uninstall your current VSCode (make sure to back up any settings/extensions if you care about them, though re-installing extensions is easy) and then install an older version. You might want to try 1.98.x or even 1.97.x. Be aware that downgrading can sometimes introduce other issues or prevent you from getting the latest features/bug fixes.

Let me know what your helpdesk says, or if you encounter any other specific errors during these steps.

Answer 4

Hi Riza,

Thank you so much for help, I tried to ran the code that you sent me in terminal and than logged in again and ran free - h and unlimited -a:

But, I still had same error...

Also I have remote server not showing up issue. So, my professor told me to uninstall everything related to VSCode and than reinstall it again when I got that error message, and I did so, but after that I can't find the >< icon at the bottom left on VSCode. When installed the remote-extension for the first time, they said after Remote-SSH is installed, I will see new >< icon at the bottom left corner, and I did, but than now, even though Remote-SSH is installed, I don't see it... is there anyway I can make it show up again?

(<-this thing)

About the help desk, I actually went to them this morning, and the help desk said since I can connect to remote, checking on local terminal, they can't do anything about it. I should ask teaching assistant (TA) about anything related to VSCode, but than TA said they need a time to figure out...so I out the our of memory part you sent me, but than they don't know how to do it...

Answer 5

This is fantastic! The ulimit -a output confirms our strong suspicion and gives us the exact culprit.

The smoking gun is right here:

virtual memory (kbytes, -v) 10240000

This means your user account on the remote server is limited to 10,240,000 kilobytes of virtual memory.

10,240,000 KB=10,240 MB=10 GB

Your user is limited to a maximum of 10 GB of virtual memory.

While 10GB sounds like a lot for a single process, the error message RangeError: WebAssembly.instantiate(): Out of memory: Cannot allocate Wasm memory for new instance clearly indicates that the latest VSCode server, running Node.js v22.15.1, is attempting to allocate WebAssembly memory that exceeds this 10GB virtual memory limit.

This is a very common issue with modern applications that use technologies like Electron/Node.js/WebAssembly, as they can sometimes demand larger virtual memory allocations, even if they don't use all of it resident in RAM.

What this means for you:

You've definitively diagnosed the problem. It is NOT a lack of overall server RAM (which you confirmed with free -h showing 165GB available).

It is NOT a problem with your password or SSH connection.\

It is NOT something you can fix yourself as a regular user, because ulimits are typically set by the system administrator.

The "Downloading VSCode Server..." loop and the missing Remote Explorer icon are all symptoms of the VSCode server failing to launch due to this memory constraint.

Your Action Plan: How to Get This Fixed by IT/System Administrators. You now have all the evidence needed based from the screenshot you shaerd.

---

Here's a sample script or explanation you can use when you go back to to whoever manages the CS server:

" I'm having a critical issue connecting to the remote server with VSCode that is preventing me from doing my assignments. I've narrowed down the problem and need your help to adjust a system setting.

My VSCode is failing to connect with the error:

RangeError: WebAssembly.instantiate(): Out of memory: Cannot allocate Wasm memory for new instance

After a thorough investigation, we found the cause:

The server itself has plenty of memory. I ran free -h and it shows 165GB of RAM available (show them your free -h screenshot). This confirms the server is not globally out of memory.

My user account, however, has a virtual memory limit that is too low. I ran ulimit -a, and it shows: virtual memory (kbytes, -v) 10240000 This means my user account is capped at 10GB of virtual memory.

The latest version of VSCode (1.101.0, released June 11, 2025) uses Node.js v22.15.1 and WebAssembly, and it appears to require more virtual memory than my current ulimit allows for its server component to launch successfully. This is why the problem started suddenly last week after my VSCode updated.

Request to increase the virtual memory (-v) ulimit for my user account . A value of a much higher number (e.g., 32000000 for 32GB, or even higher, depending on typical usage) would likely resolve this.

This is not a VSCode bug that I can fix, but a server resource configuration that needs adjustment to support the latest development tools."

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Regarding the >< icon not showing:

As mentioned, this is a symptom of the underlying memory issue. Once the VSCode server can successfully launch and connect on the remote machine (after the ulimit is adjusted), the Remote Explorer (><) icon will reappear and function normally. You don't need to do anything specific to make it show up; fixing the server connection will resolve it.

Good luck! You're very close to getting this resolved. This is a system administration task, and you've done excellent detective work to pinpoint it for them.