Cannot open exported modpack

[Evander-s]

Please confirm the following.

• I checked the existing issues for duplicate problems
• I have tried resolving the issue using the support portal
• I have ensured my Modrinth App installation is up to date

What version of the Modrinth App are you using?

0.17.5

What operating systems are you seeing the problem on?

MacOS

Describe the bug

When opening a modpack, the modrinth app downloads the content, starts extracting the overrides, and then fails with "Couldn't save files". Another note, usually when I rename the modpack to [name].zip the os can open it. Now macOS errors out with "Error 79 - Inappropriate file type or format".

Here are the details:
Install report: Create 5.2.1
Result: failed while extracting overrides (filesystem_error)
Job ID: dde359b7-ebcd-478d-9182-9f8cd6bdfaf3
Request: create_modpack_instance
Status: failed
Current phase: rolling back

Environment
App version: 0.17.5
OS: macOS 26.6.1
OS kind: macos
OS family: unix
Architecture: aarch64
Kernel: 25.6.0

Timeline

1. 2026-08-10T19:47:16.909470+00:00 Queued create_modpack_instance install
2. 2026-08-10T19:47:16.924244+00:00 Started install job
3. 2026-08-10T19:47:16.924560+00:00 Started resolving pack
4. 2026-08-10T19:47:16.924864+00:00 Started downloading pack file
5. 2026-08-10T19:47:16.939182+00:00 Started reading pack manifest
6. 2026-08-10T19:47:16.940488+00:00 Started resolving pack
7. 2026-08-10T19:47:16.944542+00:00 Started downloading content
8. 2026-08-10T19:47:34.603035+00:00 Started extracting overrides
9. 2026-08-10T19:47:34.797064+00:00 Failed while extracting overrides (filesystem_error): I/O (std) error: unexpected BufError
10. 2026-08-10T19:47:34.797065+00:00 Started rollback (delete partially-created instance local:b0d60baa-b327-4777-9c9e-7b9e5ddf9b10)
11. 2026-08-10T19:47:34.821790+00:00 Rollback completed
12. 2026-08-10T19:48:17.772316+00:00 Queued create_modpack_instance install
13. 2026-08-10T19:48:17.787788+00:00 Started install job
14. 2026-08-10T19:48:17.788242+00:00 Started resolving pack
15. 2026-08-10T19:48:17.788654+00:00 Started downloading pack file
16. 2026-08-10T19:48:17.799036+00:00 Started reading pack manifest
17. 2026-08-10T19:48:17.800778+00:00 Started resolving pack
18. 2026-08-10T19:48:17.804515+00:00 Started downloading content
19. 2026-08-10T19:48:36.244901+00:00 Started extracting overrides
20. 2026-08-10T19:48:36.478295+00:00 Failed while extracting overrides (filesystem_error): I/O (std) error: unexpected BufError
21. 2026-08-10T19:48:36.478295+00:00 Started rollback (delete partially-created instance local:03ebdd5e-6577-48a0-86f2-1e7f412f9847)
22. 2026-08-10T19:48:36.499964+00:00 Rollback completed
23. 2026-08-10T19:50:04.147364+00:00 Queued create_modpack_instance install
24. 2026-08-10T19:50:04.163398+00:00 Started install job
25. 2026-08-10T19:50:04.164246+00:00 Started resolving pack
26. 2026-08-10T19:50:04.165151+00:00 Started downloading pack file
27. 2026-08-10T19:50:04.178945+00:00 Started reading pack manifest
28. 2026-08-10T19:50:04.181198+00:00 Started resolving pack
29. 2026-08-10T19:50:04.185548+00:00 Started downloading content
30. 2026-08-10T19:50:27.959176+00:00 Started extracting overrides
31. 2026-08-10T19:50:28.234633+00:00 Failed while extracting overrides (filesystem_error): I/O (std) error: unexpected BufError
32. 2026-08-10T19:50:28.234634+00:00 Started rollback (delete partially-created instance local:670f4c70-cfaa-4bb4-8697-6307c946e32f)
33. 2026-08-10T19:50:28.257272+00:00 Rollback completed

Content activity
Completed files: 675 / 225, skipped files: 0
Expected content size: 684.7 MiB

Recently completed files

• mods/createrailwaysnavigator-neoforge-1.21.1-beta-0.9.1-C6.jar (2.0 MiB)
• mods/chloride-NEOFORGE-mc1.21.1-v1.8.1.jar.disabled (515.5 KiB)
• mods/appleskin-neoforge-mc1.21-3.0.9.jar (74.0 KiB)
• resourcepacks/FA+All_Extensions-v1.8.1.zip (415.1 KiB)
• mods/tacz-tweaks-3.0.0-alpha.10+1.21.1-neoforge.jar (4.1 MiB)
• mods/numismaticsutils-2.2-1.21.1.jar (41.2 KiB)
• mods/create_easy_structures-0.2a-neoforge-1.21.1.jar (458.5 KiB)
• mods/GlitchCore-neoforge-1.21.1-....jar (88.6 KiB)
• mods/emotecraft-for-MC1.21.1-2.4.12-neoforge.jar (841.6 KiB)
• mods/create_power_loader-2.0.5-mc1.21.1.jar (432.0 KiB)
• mods/immersive_aircraft-1.4.6+1.21.1-neoforge.jar (2.3 MiB)
• mods/NoChatRestrictions-NeoForge-MC1.21.11-v1.0.0.jar (8.9 KiB)
• mods/sodiumextras-neoforge-1.0.8-1.21.1.jar.disabled (270.5 KiB)
• mods/dragonlib-neoforge-1.21.1-beta-3.0.28.jar (2.0 MiB)
• mods/tacz-neoforge-1.21.1-1.1.8-hotfix-r6.jar (54.6 MiB)
• mods/Essential_1-4-1-1_neoforge_1-21-1.jar (49.5 MiB)
• mods/Platform-neoforge-1.21.1-1.3.3.jar (477.9 KiB)
• mods/electroenergetics-1.21.1-1.1.1.jar (4.6 MiB)
• mods/ferritecore-7.0.3-neoforge.jar (118.7 KiB)
• mods/Almanac-1.21.1-2-neoforge-1.5.2.jar (25.0 KiB)
• ... 655 more

Failure
Code: filesystem_error
Phase: extracting overrides
Message: I/O (std) error: unexpected BufError
Operation: extract modpack override
Source path: /Users/frog/Downloads/Create 5.2.1.mrpack
Target path: /Users/frog/Library/Application Support/ModrinthApp/profiles/Create 5.2.1/config/midnightlib.json
Archive entry: overrides/config/midnightlib.json

Raw snapshot
{
"job_id": "dde359b7-ebcd-478d-9182-9f8cd6bdfaf3",
"instance_id": null,
"kind": "create_modpack_instance",
"status": "failed",
"target": {
"type": "new_instance",
"instance_id": null
},
"phase": "rolling_back",
"progress": null,
"details": {
"type": "empty"
},
"display": {
"title": "Create 5.2.1",
"icon": null
},
"error": {
"code": "filesystem_error",
"phase": "extracting_overrides",
"message": "I/O (std) error: unexpected BufError",
"context": {
"operation": "extract modpack override",
"source_path": "/Users/frog/Downloads/Create 5.2.1.mrpack",
"target_path": "/Users/frog/Library/Application Support/ModrinthApp/profiles/Create 5.2.1/config/midnightlib.json",
"entry_path": "overrides/config/midnightlib.json"
}
},
"rollback_error": null,
"created": "2026-08-10T19:47:16Z",
"modified": "2026-08-10T19:50:28Z",
"finished": "2026-08-10T19:50:28Z"
}

Latest launcher log excerpt
File: /Users/frog/Library/Application Support/ModrinthApp/launcher_logs/session_20260810_154445.log
2026-08-10T15:44:45.476038-04:00 INFO theseus_gui: Initialized tracing subscriber. Loading Modrinth App!
2026-08-10T15:44:45.479744-04:00 INFO theseus_gui: Initializing app...
2026-08-10T15:44:45.748389-04:00 INFO theseus_gui::macos::deep_link: No initial payload found, creating new
2026-08-10T15:44:46.671476-04:00 ERROR get_game_version_tags: theseus::state: Attempted to get state before it is initialized - this should never happen!
2026-08-10T15:44:46.671537-04:00 ERROR get_loader_tags: theseus::state: Attempted to get state before it is initialized - this should never happen!
2026-08-10T15:44:46.672960-04:00 INFO initialize_state: theseus_gui: Initializing app event state...
2026-08-10T15:44:46.673059-04:00 INFO initialize_state: theseus_gui: Initializing app state...
2026-08-10T15:44:46.673086-04:00 INFO initialize_state:initialize_state{app_identifier="ModrinthApp"}: theseus::state: Connecting to app database
2026-08-10T15:44:46.700233-04:00 INFO initialize_state:initialize_state{app_identifier="ModrinthApp"}: theseus::state: Fetching app settings
2026-08-10T15:44:46.700464-04:00 INFO initialize_state:initialize_state{app_identifier="ModrinthApp"}: theseus::state: Initializing directories
2026-08-10T15:44:46.700928-04:00 INFO initialize_state:initialize_state{app_identifier="ModrinthApp"}: theseus::state: Initializing file watcher
2026-08-10T15:44:46.701026-04:00 INFO init_watcher: theseus::state::instances::watcher: Initing watcher
2026-08-10T15:44:46.740823-04:00 ERROR theseus::state::instances::watcher: Failed to watch directory for watcher "/Users/frog/Library/Application Support/ModrinthApp/profiles/RW server/mods": No path was found. about ["/Users/frog/Library/Application Support/ModrinthApp/profiles/RW server/mods"]
2026-08-10T15:44:47.248927-04:00 INFO connect: theseus::state::friends: Connected to friends socket
2026-08-10T15:47:13.883756-04:00 INFO theseus_gui: Handling webview open [Url { scheme: "file", cannot_be_a_base: false, username: "", password: None, host: None, port: None, path: "/Users/frog/Downloads/Create%205.2.1.mrpack", query: None, fragment: None }]
2026-08-10T15:47:13.883780-04:00 INFO theseus_gui: Handling macOS deep link
2026-08-10T15:47:13.883851-04:00 INFO theseus_gui::api::utils: handle command: /Users/frog/Downloads/Create 5.2.1.mrpack
2026-08-10T15:47:13.884023-04:00 INFO theseus_gui::api::utils: handle command: file:///Users/frog/Downloads/Create%205.2.1.mrpack
2026-08-10T15:47:16.910870-04:00 INFO create{name="Create 5.2.1" game_version="1.19.4" modloader=Vanilla loader_version=None icon_path=None link=Unmanaged}: theseus::state::instances::commands::create_instance: Creating instance at path /Users/frog/Library/Application Support/ModrinthApp/profiles/Create 5.2.1
2026-08-10T15:47:16.940749-04:00 WARN theseus::api::pack::install_mrpack: No version_id available, skipping modpack file hash caching
2026-08-10T15:47:34.797014-04:00 ERROR theseus::install::runner: Install job dde359b7-ebcd-478d-9182-9f8cd6bdfaf3 failed: I/O (std) error: unexpected BufError
2026-08-10T15:47:47.276663-04:00 ERROR theseus::state::friends: Error handling message from websocket server: Io(Os { code: 54, kind: ConnectionReset, message: "Connection reset by peer" })
2026-08-10T15:47:47.781851-04:00 INFO connect: theseus::state::friends: Connected to friends socket
2026-08-10T15:48:17.773532-04:00 INFO create{name="Create 5.2.1" game_version="1.19.4" modloader=Vanilla loader_version=None icon_path=None link=Unmanaged}: theseus::state::instances::commands::create_instance: Creating instance at path /Users/frog/Library/Application Support/ModrinthApp/profiles/Create 5.2.1
2026-08-10T15:48:17.801334-04:00 WARN theseus::api::pack::install_mrpack: No version_id available, skipping modpack file hash caching
2026-08-10T15:48:36.478235-04:00 ERROR theseus::install::runner: Install job dde359b7-ebcd-478d-9182-9f8cd6bdfaf3 failed: I/O (std) error: unexpected BufError
2026-08-10T15:49:33.468675-04:00 INFO theseus::api::jre: Expected Java version 21, and found 21 at /Users/frog/Library/Application Support/ModrinthApp/meta/java_versions/zulu21.46.19-ca-jre21.0.9-macosx_aarch64/zulu-21.jre/Contents/Home/bin/java
2026-08-10T15:49:33.549786-04:00 INFO theseus::api::jre: Expected Java version 17, and found 17 at /Users/frog/Library/Application Support/ModrinthApp/meta/java_versions/zulu17.62.17-ca-jre17.0.17-macosx_aarch64/zulu-17.jre/Contents/Home/bin/java
2026-08-10T15:49:33.574249-04:00 INFO theseus::api::jre: Expected Java version 25, and found 25 at /Users/frog/Library/Application Support/ModrinthApp/meta/java_versions/zulu25.30.17-ca-jre25.0.1-macosx_aarch64/zulu-25.jre/Contents/Home/bin/java
2026-08-10T15:49:33.597836-04:00 INFO theseus::api::jre: Expected Java version 8, and found 8 at /Users/frog/Library/Application Support/ModrinthApp/meta/java_versions/zulu8.90.0.19-ca-jre8.0.472-macosx_aarch64/zulu-8.jre/Contents/Home/bin/java
2026-08-10T15:49:43.422291-04:00 INFO theseus::api::jre: Expected Java version 25, and found 25 at /opt/local/Library/Java/JavaVirtualMachines/jdk-25-macports.jdk/Contents/Home/bin/java
2026-08-10T15:49:47.340976-04:00 INFO theseus::api::jre: Expected Java version 21, and found 21 at /Library/Java/JavaVirtualMachines/temurin-21.jre/Contents/Home/bin/java
2026-08-10T15:49:49.700210-04:00 INFO theseus::api::jre: Expected Java version 17, and found 17 at /Users/frog/Library/Application Support/ModrinthApp/meta/java_versions/zulu17.56.15-ca-jre17.0.14-macosx_aarch64/zulu-17.jre/Contents/Home/bin/java
2026-08-10T15:49:58.768196-04:00 INFO theseus::api::jre: Expected Java version 8, and found 8 at /Library/Java/JavaVirtualMachines/temurin-8.jdk/Contents/Home/bin/java
2026-08-10T15:50:04.148757-04:00 INFO create{name="Create 5.2.1" game_version="1.19.4" modloader=Vanilla loader_version=None icon_path=None link=Unmanaged}: theseus::state::instances::commands::create_instance: Creating instance at path /Users/frog/Library/Application Support/ModrinthApp/profiles/Create 5.2.1
2026-08-10T15:50:04.182263-04:00 WARN theseus::api::pack::install_mrpack: No version_id available, skipping modpack file hash caching
2026-08-10T15:50:28.234578-04:00 ERROR theseus::install::runner: Install job dde359b7-ebcd-478d-9182-9f8cd6bdfaf3 failed: I/O (std) error: unexpected BufError

Steps to reproduce

No response

Expected behavior

No response

Additional context

I have not had this problem on any other versions of the modrinth app.

[Evander-s]

This also could be an issue with macOS 26.6.1, but my cousin who is running macOS 26.5.1 also has the same problem.