OrcaSlicer fails to start when system filament library (AppData folder) contains files #647

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MrUnknownDE · 2026-04-05T16:25:00+02:00

MrUnknownDE commented

2026-04-05 16:25:00 +02:00

Originally created by @DerMalsy on 2/22/2026

Is there an existing issue for this problem?

I have searched the existing issues

OrcaSlicer Version

2.3.1

Operating System (OS)

Windows

OS Version

Windows 11 - 10.0.26200 Build 26200

Additional system information

CPU: AMD Ryzen 7 5700X3D

RAM: 32 GB

RTX3070 with driver V591.86

Mainboard: Gigabyte X470 AORUS ULTRA GAMING

BIOS: F65d (02.09.2024)

Versions affected

2.3.1

2.3.0

2.3.2 Beta 1 / 2.3.2 Beta 2

Printer

any

How to reproduce

Delete:

%APPDATA%\OrcaSlicer\system\OrcaFilamentLibrary

Launch OrcaSlicer → works again (once).

Repeat → same behavior.

The issue appears after OrcaSlicer closes and reopens, not on first launch after deleting the folder.

Actual results

The issue occurs consistently across all these versions.

Description

OrcaSlicer does not start properly if the system filament library folder inside AppData contains files.

If I completely delete the following directory:

%APPDATA%\OrcaSlicer\system\OrcaFilamentLibrary

OrcaSlicer starts successfully.

However:

On startup, OrcaSlicer automatically recreates and repopulates this folder from:

\resources\profiles\OrcaFilamentLibrary

After closing OrcaSlicer and attempting to start it again, it fails to start.

To make it start again, I must delete the entire OrcaFilamentLibrary folder again.

This behavior is 100% reproducible.

Reproduction steps

Install OrcaSlicer (2.3.1, 2.3.0, or 2.3.2 Beta).

Launch OrcaSlicer → works.

Close OrcaSlicer.

Launch OrcaSlicer again → fails to start.

OrcaSlicer fails to start unless the entire system filament library folder is deleted before each launch.

Observations

The problem occurs even with:

Fresh installation

New Windows user account

No custom presets

No modified system files

The issue is independent of version (tested multiple versions).

The files in the resources directory are valid JSON.

Manually copying files works correctly.

Expected results

OrcaSlicer should start normally even if the system filament library is already populated.

Project file & Debug log uploads

no logs because it doesnt start up. Crashed in loading screen already

Checklist of files to include

Log file
Project file

Anything else?

No response

*Originally created by @DerMalsy on 2/22/2026* ### Is there an existing issue for this problem? - [x] I have searched the existing issues ### OrcaSlicer Version 2.3.1 ### Operating System (OS) Windows ### OS Version Windows 11 - 10.0.26200 Build 26200 ### Additional system information CPU: AMD Ryzen 7 5700X3D RAM: 32 GB RTX3070 with driver V591.86 Mainboard: Gigabyte X470 AORUS ULTRA GAMING BIOS: F65d (02.09.2024) Versions affected 2.3.1 2.3.0 2.3.2 Beta 1 / 2.3.2 Beta 2 ### Printer any ### How to reproduce Delete: %APPDATA%\OrcaSlicer\system\OrcaFilamentLibrary Launch OrcaSlicer → works again (once). Repeat → same behavior. The issue appears after OrcaSlicer closes and reopens, not on first launch after deleting the folder. ### Actual results The issue occurs consistently across all these versions. Description OrcaSlicer does not start properly if the system filament library folder inside AppData contains files. If I completely delete the following directory: %APPDATA%\OrcaSlicer\system\OrcaFilamentLibrary OrcaSlicer starts successfully. However: On startup, OrcaSlicer automatically recreates and repopulates this folder from: <InstallDir>\resources\profiles\OrcaFilamentLibrary After closing OrcaSlicer and attempting to start it again, it fails to start. To make it start again, I must delete the entire OrcaFilamentLibrary folder again. This behavior is 100% reproducible. Reproduction steps Install OrcaSlicer (2.3.1, 2.3.0, or 2.3.2 Beta). Launch OrcaSlicer → works. Close OrcaSlicer. Launch OrcaSlicer again → fails to start. OrcaSlicer fails to start unless the entire system filament library folder is deleted before each launch. Observations The problem occurs even with: Fresh installation New Windows user account No custom presets No modified system files The issue is independent of version (tested multiple versions). The files in the resources directory are valid JSON. Manually copying files works correctly. ### Expected results OrcaSlicer should start normally even if the system filament library is already populated. ### Project file & Debug log uploads no logs because it doesnt start up. Crashed in loading screen already ### Checklist of files to include - [ ] Log file - [ ] Project file ### Anything else? _No response_

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Reference: github/OrcaSlicer#647