Could not load file or assembly System.Threading.Tasks.Extensions

[steelunicorn]

Using release 2024.2.0
Get error when trying to connect Postgresql database.

To reproduce:

1. Open designer
2. Data -> Add data source
3. New connection -> Postgres connection
4. You don't even need to fill fields, just click 'Test connection'
5. Error

Expected to get 'Hosts can't be null' error mesage from npgsql.dll

• OS: Windows 10
• Version 2024.2.0

Copied System.Threading.Tasks.Extensions.dll from 2022.3.0 release and that solved the issue.

[alfredoo0329]

I had the same error when connecting to MySQL from FastReport 2025.1, but with another component "System.Diagnostics.DiagnosticSource". I solved it by following the next steps:

1. Download the latest release of FastReport that works on your machine, in my case it was the 2023.3 version
2. Once you uncompress the .zip file, search the .dll file of the package the error tells you FastReport doesn´t find a match for "System.Diagnostics.DiagnosticSource.dll" or "System.Runtime.CompilerServices.Unsafe.dll" in your case
3. Copy that file to the FastReport version folder you are trying to run and replace it with the file you copied from the previous version (2023.3 -> 2025.1)
4. Open FastReport Designer again (2025.1) and the error should appear no more

Also, you would want to check if the "PublicKeyToken" that the error throws you appears in the file "Designer.exe.config" so you can be sure it will work. Otherwise, you could look for the .dll file in NuGet. However, I didn´t have to do it so I wouldn´t be sure if that could work. Good luck.