A fatal error occurred. The folder [/usr/share/dotnet/host/fxr] does not exist

Question

I can't access dotnet after an update. Reinstalling dotnet and vscode didn't help.

On Ubuntu 22.04, running dotnet --info produces the output:

A fatal error occurred. The folder [/usr/share/dotnet/host/fxr] does not exist

Brockie

Did you install dotnet using apt? Is it possible you have multiple instances of dotnet in your path? – Abernon

Heppened for me multiple times on Ubuntu 22.04 with dotnet 6. Dotnet disapears while I was working on my projects. – Hahnke

Answer 1

When .NET (Core) was first released for Linux, it was not yet available in the official Ubuntu repo. So instead, many of us added the Microsoft APT repo in order to install it.

Now, the packages are part of the Ubuntu repo, and they are conflicting with the Microsoft packages. This error is a result of mixed packages.

So you need to pick which one you're going to use, and ensure they don't mix. Personally, I decided to stick with the Microsoft packages because I figured they'll be better kept up-to-date.

First, remove all existing packages to get to a clean state:

sudo apt remove dotnet* aspnetcore* netstandard*

Then, create a file in /etc/apt/preferences.d (I named mine 99microsoft-dotnet.pref, following the convention that files in such *.d directories are typically prefixed with a 2-digit number so that they sort and load in a predictable order) with the following contents:

Package: *
Pin: origin "packages.microsoft.com"
Pin-Priority: 1001

Then, the regular update & install:

sudo apt update && sudo apt install -y dotnet-sdk-8.0

Note, the above example shows .NET 8; replace with another version if you prefer. .NET SDKs are installed side-by-side, so you can also install multiple versions.

If you would rather use the official Ubuntu packages, remove all the existing packages as above, but instead of creating the /etc/apt/preferences.d entry, just delete the Microsoft repo:

sudo rm /etc/apt/sources.list.d/microsoft-prod.list
sudo apt update
sudo apt install dotnet-sdk-7.0

However, note that the Microsoft repo contains other packages such as PowerShell, SQL Server Command-Line Tools, etc., so removing it may not be desirable.

I'm sure it's possible to make the APT config more specific to just these packages, but this is working for me for now. Hopefully Microsoft and Ubuntu work together to fix this soon.

More info on the issue and various solutions is available here:

• https://learn.microsoft.com/en-us/dotnet/core/install/linux-package-mixup
• https://github.com/dotnet/core/issues/7699

Kolomna

This solved the issue for me on Ubuntu 22.04.1. I also decided to go with Microsoft packages. – Repro

Well I followed the above steps on 22.04.01 and I am still facing the same issue. Any help ? – Thoth

@Thoth sorry I don't really have further knowledge other than what I gained from the links I included at the end. I'd suggest asking on the GitHub issue with your specific error & see if they have feedback. – Kolomna

Thanks for this. Some guide linked on MS pages specified the required file location incorrectly. This indeed works. – Radborne

This solves the problem on WSL with ubuntu 22. Thanks a lot! Would you mind explain a little bit more about how the 99microsoft-dotnet file solves this issue? Thanks! – Chokecherry

@LeOn-HanLi I just copied it from the linked github issue; it specifies that the priority of all packages coming from the microsoft repo is higher than all packages coming from the Ubuntu repo. This should be fine since the only conflicts are the dotnet ones. You could also specify that only the packages I mentioned (dotnet, aspnetcore, netstandard) should have a higher priority. More info on how to configure apt priority is here: wiki.debian.org/AptConfiguration – Kolomna

It seems that the typical extension for files in /etc/apt/preferences.d is *.pref according to this askubuntu answer. Hence, I'd rename 99microsoft-dotnet to 99microsoft-dotnet.pref. – Waikiki

@Waikiki thanks, my directory was empty so wasn't sure what to use. I updated the answer as suggested & also included info on why the "99" prefix is used. – Kolomna

Thank you so much! I had no idea about the mismatched packages, this solved my current problem as well as cleaned up some other weirdness (random crashes) I'd encountered using VSCode on Linux Mint 21. Thanks again!! – Rarebit

Although this works I keep getting the same problem after few days – Imbrue

@Imbrue yeah I've had it occur again a couple times too. I'm guessing there's something about the settings file that isn't quite right but it's also just barely not annoying enough for me to want to dive into it further haha. Now that .NET/Core isn't moving as quickly as it was in the 2/3/5 days I might just switch back to the Ubuntu packages. – Kolomna

I think the recurring problem happens when the package version in the ubuntu repository is higher than the one in the microsoft repo. If I run apt upgrade with --allow-downgrades that seems to keep me on the correct version. – Luculent

@MikeFrank thanks, I figured it might have to do with their version numbers but didn't know about --allow-downgrades, I'll try that if it happens again! – Kolomna

This worked for the initial installation, but then we got bitten by unattended-upgrades creating the same mess again. In case anyone else runs into this see github.com/dotnet/core/issues/7699#issuecomment-1780733437 – Rede

Solved it for me on Ubuntu 23.04 – Manatarms

could you help me here? #78323204 – Adp

Answer 2

I had a same error and I did install .Net with microsoft packages. I think the problem is if you have had older .Net or mixing scenarios regarding Ubuntu package and .Net packages(f.x via Jammy or PMC). BTW, I solved my problem to stick with Ubuntu packages and did run this bash script :

# First, try to remove/uninstall older .Net, if any, then install .Net 6
echo "$(tput setaf 3)Installing .Net 6$(tput sgr0)"
sudo apt remove 'dotnet*'
sudo apt remove 'aspnetcore*'
sudo apt remove 'netstandard*'
sudo rm /etc/apt/sources.list.d/microsoft-prod.list
sudo rm /etc/apt/sources.list.d/microsoft-prod.list.save
sudo apt update
sudo apt install dotnet6

Erdda

I think this should be the accepted answer. YES the accepted one works but quite often you'll find yourself in the same scenario where you have to remove and install again because, for some weird reason, Ubuntu does its own things and messes things up. I found myself having to re-install quite often and that's not ON. – Torrey

Sticking with the Ubuntu packages is fine but you may well run into the issue that the Ubuntu repository takes longer to update and release their packages. E.G. .net8 has been out for two weeks now and isn't available on 22.04 only 23.04 – Dizon

Answer 3

I've got this error message after:

sudo apt install dotnet-host

This solved it for me:

sudo apt install dotnet-sdk-6.0

Aimless

Did not work for me – Candicecandid

On a clean installation of Ubuntu 23.04, per Ubuntu's auto recommendation when attempting to execute dotnet but it wasn't installed, I also ran apt install dotnet-host and ran into this problem. I can confirm that using the suggested workaround (in my case, pkg remove dotnet-host; pkg install dotnet-sdk-7.0) worked. – Elliottellipse

Answer 4

1. First of all, you need to run using super user

sudo su

insert you password and go to seccond point:

2. If you only want to run a .net code

install dotnet-host-7.0

2.1) If you want to develope systems using .net

apt install dotnet-sdk-7.0

---

If you want to remove olders versions:

sudo apt remove 'dotnet*'
sudo apt remove 'aspnetcore*'
sudo apt remove 'netstandard*'

Waltner

Answer 5

In case anyone encounters the same error right now (2023 July), I've tried a lot of the comments and blog posts, but this worked for me perfectly:

There is a part:

dotnet --version
A fatal error occurred. The folder [/usr/share/dotnet/host/fxr] does not exist
Great.

Since there, just follow along and it works :)

Not my solution, all respect to the author of this post:

https://alexanderzeitler.com/articles/fixing-my-bricked-dotnet-sdk-6-installation-on-xubuntu-ubuntu-after-dotnet-7-sdk-installation/

Sequel

While this link may answer the question, it is better to include the essential parts of the answer here and provide the link for reference. Link-only answers can become invalid if the linked page changes. – Headstrong

Answer 6

In my case I had to remove /etc/apt/sources.list.d/mssql-release.list which had been installed as part of some other work where I needed ODBC drivers. It says mssql, but that's the same source as the MS dotnet packages, causing the interference.

To stick with just the Ubuntu packages:

sudo rm -f /etc/apt/sources.list.d/mssql-release.list
sudo apt purge dotnet* aspnetcore* netstandard*
sudo apt update
sudo apt install dotnet-sdk-6.0

Madoc

Answer 7

I had this error when I created a new VS Code Dev Container using Ubuntu Jammy and selecting the "dotnet CLI" feature. I ended up switching my Dev Container to use Focal and the problem went away.

Overabound

Answer 8

In my case, i needed to do an "Upgrade" before an "Update".

sudo apt remove dotnet* aspnetcore* netstandard*
sudo apt upgrade
sudo apt update
sudo apt install dotnet-sdk-6.0

Bouffant

Answer 9

sudo apt remove dotnet-sdk* dotnet-host* dotnet* aspnetcore* netstandard*

sudo apt remove aspnetcore*

sudo apt remove netstandard*

sudo apt remove dotnet-host*

sudo apt purge dotnet-sdk* dotnet-host* dotnet* aspnetcore* netstandard*

sudo rm -f /etc/apt/sources.list.d/mssql-release.list

sudo rm /etc/apt/sources.list.d/microsoft-prod.list

sudo rm /etc/apt/sources.list.d/microsoft-prod.list.save

sudo apt update

Install by App Center: .Net Core SDK, Stable 8.0.101

there is no need for other installations!

(sudo snap install dotnet-sdk #Installed by App Center

sudo apt install dotnet-sdk-8.0 #Installed by App Center

sudo apt install dotnet-host-8.0 #Installed by dotnet-sdk-8.0)

dotnet workload update

source ~/.bashrc

dotnet sdk check

dotnet --info

dotnet --list-sdks

8.0.100 [/snap/dotnet-sdk/233/sdk]

dotnet --version

8.0.100

Haematosis

Answer 10

For those running into this problem on MacOS (installed via MacPorts): There seem to be three ports needed to actually run it:

sudo port install dotnet-cli
sudo port install dotnet-runtime-8
sudo port install dotnet-sdk-8

(Or maybe with differing version numbers) I had the same error message as in the original post after installing just dotnet-cli, the second install of dotnet-runtime-8 changed the error-message and the third install of dotnet-sdk-8 made it finally work.

Ihs