- Loaders
- Fabric
- Downloads on Modrinth
- 1.6M
- Followers on Modrinth
- 134
- versions
- 20
- Updated
- September 16, 2026Sep 16
- Published
- in 2023
At a glance
Install in the game only; not needed on the server
Note
This mod no longer seems to be required as of MC 1.20.5. Nonetheless, interactions between mods might still cause an issue, so I will keep updating it for the time being. If you experience no lag spikes, you can safely remove this mod.
Original Description
In vanilla minecraft, the list of resource packs is refreshed by scanning all possible sources synchronously.
Generally, this is not a problem, but in the resource pack organizer screen, this scan is performed whenever it is resized and every twenty ticks.
If another mod (such as Respackopts) hooks into the pack scan and increases its duration even slightly, this leads to major lag spikes and makes the screen near-unusable when using more than a few packs.
This mod fixes that issue by moving this computation to another thread and scheduling a scan task on those events instead, drastically improving perceived performance.
Since the vanilla code is designed for synchronous execution, this can cause issues like crashes in edge cases, but worked well enough in my testing.
FAQ
How to install Async Pack Scan?
Install Fabric for your Minecraft version, download Async Pack Scan for the same version and loader, put the file into the mods folder and launch the game with the loader profile.
Which Minecraft versions does Async Pack Scan support?
Async Pack Scan has builds for Minecraft 1.20, 1.20.2, 1.20.4–1.20.5, 1.21–26.3.
Is Async Pack Scan needed on the server?
Client only — no need to install it on the server