Is there an existing issue for this?

• I have searched the existing issues

Is the issue reproducible in Notepad++ without plugin?

• I have tried Notepad++ without plugin

Is the issue reproducible in portable version of Notepad++?

• I have tried portable version of Notepad++

Does the issue affect SciTE?

• I have tried SciTE

Description of the Issue

When creating a new UDL in v8.9.2 while file open in that UDL, it causes Notepad++ to crash. Also crashes if you apply that new UDL to the file. See STR

Steps To Reproduce

1. Launch fresh portable v8.9.2
2. In Language > User Defined Language > Define your language..., set KEYWORDS1 = ABILITYCATEGORY
3. Paste the following:

   ABILITYCATEGORY:Haunted					VISIBLE:QUALIFY
   ABILITYCATEGORY:Background / Quirk		VISIBLE:INVISIBLE
   ABILITYCATEGORY:Arcane					VISIBLE:QUALIFY
   

4. Set Language > User-Defined
5. Crash

Current Behavior

Crashes at step 5. Creates NppDump.dmp, attached.

Expected Behavior

Should not crash. Should let you create UDL.

v8.9.1 fresh portable confirmed to still work, so it's a regression in v8.9.2

Debug Information

Notepad++ v8.9.2   (64-bit)
Build time: Feb 13 2026 - 02:47:53
Scintilla/Lexilla included: 5.5.8/5.4.6
Boost Regex included: 1_90
pugixml included: 1.15
nlohmann JSON included: 3.12.0
Path: C:\usr\local\apps\npp\npp.8.9.2.portable.x64\notepad++.exe
Command Line: 
Admin mode: OFF
Local Conf mode: ON
Cloud Config: OFF
Periodic Backup: ON
Placeholders: OFF
Scintilla Rendering Mode: SC_TECHNOLOGY_DIRECTWRITE (1)
Multi-instance Mode: monoInst
asNotepad: OFF
File Status Auto-Detection: cdEnabledNew (for current file/tab only)
Dark Mode: OFF
Display Info:
    primary monitor: 1920x1080, scaling 100%
    visible monitors count: 1
    installed Display Class adapters: 
        0000: Description - Intel(R) UHD Graphics 770
        0000: DriverVersion - 32.0.101.7077
OS Name: Windows 11 Home (64-bit)
OS Version: 24H2
OS Build: 26100.7840
Current ANSI codepage: 1252
Plugins: 
    mimeTools (3.1)
    NppConverter (4.7)
    NppExport (0.4)

Anything else?

If I am running off of installed v8.9.2, it tries to write NppDump.dmp in the c:\program files\notepad++ directory, but doesn't get permission, so silently writes no dumpfile (I don't know if it doesn't bother trying the ask-for-UAC code that a normal file-save will do). This bug in the dump writing means that people who don't try to replicate a crash in portable might never get the dumpfile that you ask for. It should try that directory, then try asking for UAC, and if both of those fail, it should put it in the C:\Users\<username>\AppData\Local\Temp\Notepad++ RECOV where you put the recovered temp files.