Very slow launch compared to Notepad2

[GeeZuZz]

This application takes up to 2 seconds to launch, while Notepad2-mod launches instantly. Don't know if this is a bug, or a necessary side effect of the new features?

Using 6.24.1221.1

[inoyakaigor]

Agreed. I have the same problem.
Notepad3 (x64) 6.24.1221.1
Windows 11 24H2 26100.4202
Previous builds hasn't this problem but I don't sure it is because of problem in Notepad3 or Microsoft has changed something in Windows.
Even when UI didn't show yet I can paste text into Notepad's windows and it will appear when UI show.
Video proof https://github.com/user-attachments/assets/790ec19d-f69b-4397-a140-94ed0b2db4ec

[autumoon]

This seems to be an issue with your system. I tested it myself using version 6.24.1221.1 and got instant results every time. I also watched your video proof—this appears to be an isolated incident. I recommend trying a different environment to test, testing within a virtual machine, or if necessary, considering reinstalling your OS.

[aleegreat]

I have the same problem.
Notepad3 (x64) 6.25.822.1
Windows 11

[RaiKoHoff]

PR #5546 optimizes NP3's start-up times (ShowWindow).
Unfortunately, there are external factors not controllable by Notepad3 :

 EXTERNAL FACTORS (Not Controllable by Notepad3 Code)

 1. Windows Defender / Antivirus Scanning (0-3000ms)
 - On first launch after download, Windows SmartScreen/Defender scans the unsigned executable
 - .exe not in cache → real-time protection full scan of binary
 - Why "not all users": Users with Defender exclusions, or after repeated launches (binary cached), see no delay
 - Evidence: This matches the "2-4 seconds" exactly and the "not all users" pattern

 2. SegmentHeap Initialization (manifest)
 - res/Notepad3.exe.manifest declares <heapType>SegmentHeap</heapType>
 - SegmentHeap has higher first-use initialization cost than standard NT heap
 - On first process creation after boot: kernel allocates segment structures
 - Estimated: 50-200ms additional on cold start

 3. Disk I/O Latency (HDD vs SSD)
 - Users on HDDs will experience all file operations 5-10x slower than SSD
 - INI file loading, theme parsing, 27 language DLL existence checks, icon loading — all disk-bound
 - This alone could explain the full 2-4 seconds on HDD

 4. DLL Delay-Load Chain
 - UxTheme.dll is delay-loaded (__HrLoadAllImportsForDll)
 - comctl32.dll loaded explicitly in FixDarkScrollBar()
 - ole32.dll loaded by CoInitializeEx()/OleInitialize()
 - Each DLL load triggers: disk read + relocation + DllMain + Defender scan
 - On cold start (not in filesystem cache): ~100-300ms per DLL

 ANALYSIS: WHY "NOT ALL USERS"

 The delay is heavily dependent on:
 1. Antivirus: Defender real-time protection enabled → +1-3s; excluded/disabled → +0s
 2. Disk type: HDD → +1-3s for all I/O; SSD → +0.1s
 3. Cold vs warm start: First launch after boot vs. repeated launch (DLLs/INI cached)
 4. INI file size: Large INI with many settings → slower parse
 5. Language pack count: 27 file existence checks regardless of language used
 6. Previous instance state: If another Notepad3 is hung → ActivatePrevInst blocks up to 5s
 7. Dark mode: Win10+ with dark mode available → UxTheme delay-load; older Windows → skipped