Eziriz's ".NET Reactor" expired
Here's what my startup log says today:
9.10.19 (X64) 2026-08-27T10:03:02 GuiAppHost
Exception - This assembly is protected by an unregistered version of Eziriz's ".NET Reactor"!
Source=APS.Shared.Wpf
ActiproSoftware.Windows.Themes.Generation.ThemeDefinition..ctor(String)
LINQPad.UI.ThemerX.Init(Boolean)
LINQPad.UIProgram.InitThemeForLINQPadGui()
LINQPad.UIProgram.Go(String[])
The failing assembly is APS.Shared.Wpf — Actipro's WPF control library, which is bundled inside LINQPad.GUI.dll. It's not LINQPad's own code, and it's not a driver or NuGet package of yours. That component was protected with an unregistered (trial) .NET Reactor licence, and trial-protected assemblies refuse to run past a date baked in at protection time. It blows up during theme initialisation, which runs before the window appears — hence "won't start".
The date is the proof. Your log shows LINQPad 9.10.19 starting normally at 09:49 yesterday, and every launch today from 10:03 onward hitting this. Same build, untouched on disk since 13 August. Nothing changed on your machine — the assembly just reached its expiry overnight.
Claude also checked the install is genuine: LINQPad9.exe, LINQPad.Runtime.dll and LINQPad.GUI.dll all carry valid Authenticode signatures from CN=Joseph Albahari. Nothing is tampered with, so reinstalling the same build won't help — it's the same bytes.
Comments
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Same issue: as soon as I update the version, it never starts and keeps giving me an error
This assembly is protected by an unregistered version of Eziriz's ".NET Reactor"! This assembly won't further work.
This is bad; all my work scripts are there, and I need to run them. Now I can't!!!
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@syedadeel2 said:
Same issue: as soon as I update the version, it never starts and keeps giving me an errorThis assembly is protected by an unregistered version of Eziriz's ".NET Reactor"! This assembly won't further work.
This is bad; all my work scripts are there, and I need to run them. Now I can't!!!
The issue appears limited to the GUI.
While it isn’t ideal, until we have a solution, it may be worth considering whether you can achieve what you need by running your LINQPad scripts from the command line using LPRun. -
I have reverted to LINQPad 8 which doesn't have the issue
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It's causing a show stopper for my business.
I'll attempt the downgrade to LP8 for the time being.
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I'm onto it - there should be a new build ready in less than an hour.
Note that you will need to re-install LINQPad. More info soon.
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I'm experiencing the same issue.
For now, I'm using LINQPad 9 beta (v9.10.12), and it's working fine at the moment. -
It's now been fixed. Note that this will require downloading and installing LINQPad 9 again for affected users. Please accept my apologies.
I will be following up shortly with a full incident report shortly.
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First, I want to apologize to everyone over this.
TLDR: The issue is now fixed but LINQPad 9 will need to be downloaded again and reinstalled from https://www.linqpad.net/LINQPad9.aspx.
Background
LINQPad 9 started reporting a critical startup failure today. It was indeed caused by obfuscation in the Actipro editor assemblies. The fault was mine, because I'm responsible for re-obfuscating the assemblies in accordance with the blueprint licensing terms.
What happened
A hardware change on the build machine around two weeks ago invalidated the obfuscator license. This put an effective expiry date into the builds.
What's been done to prevent this recurring
The build script now parses the output from the obfuscator, failing if a licensing message is not present.
Again, please accept my apologies. I'm upset by the disruption that this has caused.
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Does this apply to the beta channel as well as release?
And does it just apply between specific versions of LINQPad 9?
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Right now, it affects the 9.10 RTM release versions below 9.10.20.
Over time, it will also affect beta versions below 9.11.5.
