(Ubuntu 18.04 LTS) Could not load file or assembly 'netstandard, Version=2.0.0.0

1

I’m encountering the following errors when attempting to run a backup job under Ubuntu 18.04 LTS. Mono version is 6.12.0.200. Duplicati - 2.0.7.1_beta_2023-05-25

(in Web interface)
Could not load file or assembly ‘netstandard, Version=2.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51’ or one of its dependencies.

(at Ubuntu command line)
Failed to load module “canberra-gtk-module”
Failed to send notification: System.IO.FileNotFoundException: Could not load file or assembly ‘notify-sharp, Version=0.4.0.0, Culture=neutral, PublicKeyToken=2df29c54e245917a’ or one of its dependencies.
File name: ‘notify-sharp, Version=0.4.0.0, Culture=neutral, PublicKeyToken=2df29c54e245917a’
at Duplicati.GUI.TrayIcon.GtkRunner.NotifyUser (System.String title, System.String message, Duplicati.GUI.TrayIcon.NotificationType type) [0x00002] in <9128bf13baf6406fa6155e78725fe6c0>:0

I am trying to backup to Backblaze B2.

Thanks for your help!

2

Was it ever working?

Have you installed these packages from the Install guide:

sudo apt install mono-devel gtk-sharp2

At least the GTK seems to be part of the problem, and I think the default mono package doesn’t have all the libraries.

3

netstandard is part of Mono. Mono itself is loaded in Ubuntu using a PPA, that is, it’s basically not supported in any way by Ubuntu. This means that to get support, you have to rely on Mono and exclusively on Mono. And it’s not realist to expect Mono to support an obsolete operating system.
In other words, sorry, but it will most probably not work.

4

Welcome to the forum @geee1w

Supported by this forum post and a 2013 decision from the mono devs, still with an open issue on

Please see if following the installation directions provides you with assemblies reported as missing.
Attempting to trace with dpkg and apt series of tools gave a clearer answer for mono than graphics.

5

No its a new install. I encounter these errors when trying to install those packages:

The following packages have unmet dependencies:
gtk-sharp2-gapi : Depends: libc6 (>= 2.31) but 2.27-3ubuntu1.6 is to be installed or
libc6.1 (>= 2.31) but it is not installable or
libc0.1 (>= 2.31) but it is not installable
libgdiplus : Depends: libc6 (>= 2.29) but 2.27-3ubuntu1.6 is to be installed
libglib2.0-cil : Depends: libglib2.0-0 (>= 2.64.1) but 2.56.4-0ubuntu0.18.04.9 is to be installed
libgtk2.0-cil : Depends: libatk1.0-0 (>= 2.35.1) but 2.28.1-1 is to be installed
Depends: libgdk-pixbuf2.0-0 (>= 2.40.0+dfsg) but 2.36.11-2 is to be installed
Depends: libglib2.0-0 (>= 2.64.1) but 2.56.4-0ubuntu0.18.04.9 is to be installed
Depends: libpango-1.0-0 (>= 1.44.7) but 1.40.14-1ubuntu0.1 is to be installed
Depends: libpangocairo-1.0-0 (>= 1.44.7) but 1.40.14-1ubuntu0.1 is to be installed

I think this means I need to update to ubuntu 22 but I’m not sure. Instructions on the duplicati site don’t mention the minimum OS version.

6

Did you make this file, per the directions?

$ cat /etc/apt/sources.list.d/mono-official-stable.list
deb https://download.mono-project.com/repo/ubuntu stable-bionic main
$

I’m not sure where your gtk-sharp2-gapi is coming from. You could try a command like:

$ apt show --all-versions gtk-sharp2
Package: gtk-sharp2
Version: 2.12.45-0xamarin19+ubuntu1804b1
Priority: optional
Section: libs
Maintainer: Debian CLI Libraries Team <pkg-cli-libs-team@lists.alioth.debian.org>
Installed-Size: 147 kB
Depends: gtk-sharp2-examples (= 2.12.45-0xamarin19+ubuntu1804b1), gtk-sharp2-gapi (= 2.12.45-0xamarin19+ubuntu1804b1), libglade2.0-cil-dev (= 2.12.45-0xamarin19+ubuntu1804b1), libglib2.0-cil-dev (= 2.12.45-0xamarin19+ubuntu1804b1), libgtk2.0-cil-dev (= 2.12.45-0xamarin19+ubuntu1804b1), monodoc-gtk2.0-manual (= 2.12.45-0xamarin19+ubuntu1804b1)
Homepage: http://www.mono-project.com/GtkSharp
Download-Size: 142 kB
APT-Manual-Installed: yes
APT-Sources: https://download.mono-project.com/repo/ubuntu stable-bionic/main amd64 Packages
Description: GTK# 2.12 suite, CLI bindings for GTK+
 GTK# 2.12 is a CLI (.NET) language binding for the GTK+ 2.12 toolkit
 .
 gtk-sharp2 is a metapackage containing dependencies for the GTK# 2.12 suite.

Package: gtk-sharp2
Version: 2.12.40-2
Priority: optional
Section: universe/libs
Origin: Ubuntu
Maintainer: Ubuntu Developers <ubuntu-devel-discuss@lists.ubuntu.com>
Original-Maintainer: Debian CLI Libraries Team <pkg-cli-libs-team@lists.alioth.debian.org>
Bugs: https://bugs.launchpad.net/ubuntu/+filebug
Installed-Size: 148 kB
Depends: gtk-sharp2-examples (= 2.12.40-2), gtk-sharp2-gapi (>= 2.12.40-2), gtk-sharp2-gapi (<< 2.12.40-2.~), libglade2.0-cil-dev (>= 2.12.40-2), libglade2.0-cil-dev (<< 2.12.40-2.~), libglib2.0-cil-dev (>= 2.12.40-2), libglib2.0-cil-dev (<< 2.12.40-2.~), libgtk2.0-cil-dev (>= 2.12.40-2), libgtk2.0-cil-dev (<< 2.12.40-2.~), monodoc-gtk2.0-manual (= 2.12.40-2)
Homepage: http://www.mono-project.com/GtkSharp
Download-Size: 1,844 B
APT-Sources: http://archive.ubuntu.com/ubuntu bionic/universe amd64 Packages
Description: GTK# 2.10 suite, CLI bindings for GTK+
 GTK# 2.10 is a CLI (.NET) language binding for the GTK+ 2.10 toolkit
 .
 gtk-sharp2 is a metapackage containing dependencies for the GTK# 2.10 suite.

$

This is Linux Mint 19.3, based on Ubuntu 18.04, and you can see I got the mono-project.com lib.

7

Thanks for your help, sorry I wasn’t able to get back to you sooner!

here is what I get when I try to install mono-complete:

sudo apt install mono-complete
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help resolve the situation:

The following packages have unmet dependencies:
 mono-complete : Depends: mono-runtime (= 6.12.0.200-0xamarin2+ubuntu2004b1) but 6.12.0.200-0xamarin2+ubuntu1804b1 is to be installed
                 Depends: mono-runtime-sgen (= 6.12.0.200-0xamarin2+ubuntu2004b1) but 6.12.0.200-0xamarin2+ubuntu1804b1 is to be installed
                 Depends: mono-llvm-support (= 6.12.0.200-0xamarin2+ubuntu2004b1) but 6.12.0.200-0xamarin2+ubuntu1804b1 is to be installed
                 Depends: libmono-2.0-1 (= 6.12.0.200-0xamarin2+ubuntu2004b1) but 6.12.0.200-0xamarin2+ubuntu1804b1 is to be installed
                 Depends: mono-utils (= 6.12.0.200-0xamarin2+ubuntu2004b1) but it is not going to be installed
                 Depends: mono-devel (= 6.12.0.200-0xamarin2+ubuntu2004b1) but it is not going to be installed
                 Depends: mono-mcs (= 6.12.0.200-0xamarin2+ubuntu2004b1) but it is not going to be installed
                 Depends: mono-roslyn (= 6.12.0.200-0xamarin2+ubuntu2004b1) but it is not going to be installed
                 Depends: mono-csharp-shell (= 6.12.0.200-0xamarin2+ubuntu2004b1) but it is not going to be installed
                 Depends: mono-4.0-gac (= 6.12.0.200-0xamarin2+ubuntu2004b1) but 6.12.0.200-0xamarin2+ubuntu1804b1 is to be installed
                 Depends: monodoc-base (= 6.12.0.200-0xamarin2+ubuntu2004b1) but 6.12.0.200-0xamarin2+ubuntu1804b1 is to be installed
                 Depends: libmono-cil-dev (= 6.12.0.200-0xamarin2+ubuntu2004b1) but it is not going to be installed
                 Depends: referenceassemblies-pcl but it is not going to be installed
                 Depends: msbuild but it is not going to be installed
E: Unable to correct problems, you have held broken packages.
8

None of the questions or tests requested above your post were done.
Did you clear up gtk-sharp2 dependencies, or just test mono instead?

For mono, you can attempt a similar test as requested for gtk-sharp2:
apt show --all-versions mono-complete to see it’s still showing

I’m not sure how you’re getting what looks like the “focal” (20.04) one.
Maybe you can search: grep -R focal /etc/apt/sources.list*

If anybody out there is an apt or .deb or repo expert, please help out.
I’m rarely on Linux.

9

I’m not very advanced with ubuntu. I just cleared what I was doing before and tried again. Here is the result of the commands

apt show --all-versions mono-complete
Package: mono-complete
Version: 6.12.0.200-0xamarin2+ubuntu2004b1
Priority: optional
Section: cli-mono
Source: mono
Maintainer: Debian Mono Group <pkg-mono-group@lists.alioth.debian.org>
Installed-Size: 62.5 kB
Depends: mono-runtime (= 6.12.0.200-0xamarin2+ubuntu2004b1), mono-runtime-sgen (= 6.12.0.200-0xamarin2+ubuntu2004b1), mono-llvm-support (= 6.12.0.200-0xamarin2+ubuntu2004b1), libmono-2.0-1 (= 6.12.0.200-0xamarin2+ubuntu2004b1), libmono-profiler (= 6.12.0.200-0xamarin2+ubuntu2004b1), mono-utils (= 6.12.0.200-0xamarin2+ubuntu2004b1), mono-devel (= 6.12.0.200-0xamarin2+ubuntu2004b1), mono-mcs (= 6.12.0.200-0xamarin2+ubuntu2004b1), mono-roslyn (= 6.12.0.200-0xamarin2+ubuntu2004b1), mono-csharp-shell (= 6.12.0.200-0xamarin2+ubuntu2004b1), mono-4.0-gac (= 6.12.0.200-0xamarin2+ubuntu2004b1), mono-4.0-service (= 6.12.0.200-0xamarin2+ubuntu2004b1), monodoc-base (= 6.12.0.200-0xamarin2+ubuntu2004b1), monodoc-manual (= 6.12.0.200-0xamarin2+ubuntu2004b1), libmono-cil-dev (= 6.12.0.200-0xamarin2+ubuntu2004b1), referenceassemblies-pcl, msbuild, ca-certificates-mono (= 6.12.0.200-0xamarin2+ubuntu2004b1)
Homepage: http://www.mono-project.com/
Download-Size: 32.6 kB
APT-Sources: https://download.mono-project.com/repo/ubuntu stable-focal/main amd64 Packages
Description: complete Mono runtime, development tools and all libraries
 Mono is a platform for running and developing applications based on the
 ECMA/ISO Standards. Mono is an open source effort led by Xamarin. Mono
 provides a complete CLR (Common Language Runtime) including compiler and
 runtime, which can produce and execute CIL (Common Intermediate Language)
 bytecode (aka assemblies), and a class library.
 .
 This is a metapackage and pulls in the Mono runtime, development tools and
 all libraries.
 .
 Install this package if you want to run software for Mono or Microsoft
 .NET which you are not installing from a Debian package.
 .
 For packagers: This package is not to be used as dependency for packages!
 You should build-depend on cli-common-dev and the needed libraries
 instead.

Package: mono-complete
Version: 6.12.0.200-0xamarin2+ubuntu1804b1
Priority: optional
Section: cli-mono
Source: mono
Maintainer: Debian Mono Group <pkg-mono-group@lists.alioth.debian.org>
Installed-Size: 62.5 kB
Depends: mono-runtime (= 6.12.0.200-0xamarin2+ubuntu1804b1), mono-runtime-sgen (= 6.12.0.200-0xamarin2+ubuntu1804b1), mono-llvm-support (= 6.12.0.200-0xamarin2+ubuntu1804b1), libmono-2.0-1 (= 6.12.0.200-0xamarin2+ubuntu1804b1), libmono-profiler (= 6.12.0.200-0xamarin2+ubuntu1804b1), mono-utils (= 6.12.0.200-0xamarin2+ubuntu1804b1), mono-devel (= 6.12.0.200-0xamarin2+ubuntu1804b1), mono-mcs (= 6.12.0.200-0xamarin2+ubuntu1804b1), mono-roslyn (= 6.12.0.200-0xamarin2+ubuntu1804b1), mono-csharp-shell (= 6.12.0.200-0xamarin2+ubuntu1804b1), mono-4.0-gac (= 6.12.0.200-0xamarin2+ubuntu1804b1), mono-4.0-service (= 6.12.0.200-0xamarin2+ubuntu1804b1), monodoc-base (= 6.12.0.200-0xamarin2+ubuntu1804b1), monodoc-manual (= 6.12.0.200-0xamarin2+ubuntu1804b1), libmono-cil-dev (= 6.12.0.200-0xamarin2+ubuntu1804b1), referenceassemblies-pcl, msbuild, ca-certificates-mono (= 6.12.0.200-0xamarin2+ubuntu1804b1)
Homepage: http://www.mono-project.com/
Download-Size: 32.6 kB
APT-Sources: https://download.mono-project.com/repo/ubuntu stable-bionic/main amd64 Packages
Description: complete Mono runtime, development tools and all libraries
 Mono is a platform for running and developing applications based on the
 ECMA/ISO Standards. Mono is an open source effort led by Xamarin. Mono
 provides a complete CLR (Common Language Runtime) including compiler and
 runtime, which can produce and execute CIL (Common Intermediate Language)
 bytecode (aka assemblies), and a class library.
 .
 This is a metapackage and pulls in the Mono runtime, development tools and
 all libraries.
 .
 Install this package if you want to run software for Mono or Microsoft
 .NET which you are not installing from a Debian package.
 .
 For packagers: This package is not to be used as dependency for packages!
 You should build-depend on cli-common-dev and the needed libraries
 instead.

Package: mono-complete
Version: 4.6.2.7+dfsg-1ubuntu1
Priority: optional
Section: universe/cli-mono
Source: mono
Origin: Ubuntu
Maintainer: Ubuntu Developers <ubuntu-devel-discuss@lists.ubuntu.com>
Original-Maintainer: Debian Mono Group <pkg-mono-group@lists.alioth.debian.org>
Bugs: https://bugs.launchpad.net/ubuntu/+filebug
Installed-Size: 60.4 kB
Depends: mono-runtime (= 4.6.2.7+dfsg-1ubuntu1), mono-runtime-sgen (= 4.6.2.7+dfsg-1ubuntu1), libmono-2.0-1 (= 4.6.2.7+dfsg-1ubuntu1), libmono-profiler (= 4.6.2.7+dfsg-1ubuntu1), mono-utils (= 4.6.2.7+dfsg-1ubuntu1), mono-jay (= 4.6.2.7+dfsg-1ubuntu1), mono-devel (= 4.6.2.7+dfsg-1ubuntu1), mono-mcs (= 4.6.2.7+dfsg-1ubuntu1), mono-csharp-shell (= 4.6.2.7+dfsg-1ubuntu1), mono-4.0-gac (= 4.6.2.7+dfsg-1ubuntu1), mono-4.0-service (= 4.6.2.7+dfsg-1ubuntu1), monodoc-base (= 4.6.2.7+dfsg-1ubuntu1), monodoc-manual (= 4.6.2.7+dfsg-1ubuntu1), libmono-cil-dev (= 4.6.2.7+dfsg-1ubuntu1), ca-certificates-mono (= 4.6.2.7+dfsg-1ubuntu1)
Homepage: http://www.mono-project.com/
Download-Size: 10.3 kB
APT-Sources: http://ca.archive.ubuntu.com/ubuntu bionic/universe amd64 Packages
Description: complete Mono runtime, development tools and all libraries
 Mono is a platform for running and developing applications based on the
 ECMA/ISO Standards. Mono is an open source effort led by Xamarin. Mono
 provides a complete CLR (Common Language Runtime) including compiler and
 runtime, which can produce and execute CIL (Common Intermediate Language)
 bytecode (aka assemblies), and a class library.
 .
 This is a metapackage and pulls in the Mono runtime, development tools and
 all libraries.
 .
 Install this package if you want to run software for Mono or Microsoft
 .NET which you are not installing from a Debian package.
 .
 For packagers: This package is not to be used as dependency for packages!
 You should build-depend on cli-common-dev and the needed libraries
 instead.


grep -R focal /etc/apt/sources.list*
/etc/apt/sources.list:deb https://download.mono-project.com/repo/ubuntu stable-focal main
/etc/apt/sources.list:# deb-src https://download.mono-project.com/repo/ubuntu stable-focal main

It will probably be quicker for me to just move to 22.04 as I’m not able to deviate much from written step by step instructions.

10

somehow got on your system. It’s not in any directions I can find, but I’d guess it’s why your mono is coming in for focal (20.04) and not finding 20.04 dependencies on18.04. 22.04 may be an issue too.

Unfortunately the mono project hasn’t published 22.04 directions and (maybe therefore?) Duplicati’s manual hasn’t either, yet both the forum and GitHub issues has people who got mono. Of concern is:

and I’m worried about lack of jammy (22.04) names in
https://download.mono-project.com/repo/ubuntu/dists/

Need someone who knows more about repos and apt configuration (and ideally mono on 22.04).

11

I concur with this comment (comment that was never replied to)

following these instructions (meant for Ubuntu 20.04):

sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF 
echo "deb https://download.mono-project.com/repo/ubuntu stable-focal main" | sudo tee /etc/apt/sources.list.d/mono-official-stable.list
sudo apt update
sudo apt install mono-complete

one can run ‘mono’ without problem, and Duplicati can be installed.
I have a VM under Kubuntu 22.04 where I tested successfully the most recent stable release in graphical mode (the trayicon stuff).

Edit: all this is done of course on a clean installation. Attempting to upgrade the distro on a damaged installation with standard Ubuntu instructions will usually lead to disaster.

1 Like
12

Thanks, I found it was faster to simply clean install 22.04.