HMCL-dev/HMCL · error · IOException

Cannot parse the version of

Error message

Cannot parse the version of 

What it means

Thrown while exporting a MultiMC modpack when the instance's game version cannot be determined (GameVersionNumber.unknown()). The MultiMC mmc-pack.json must include a net.minecraft component with an explicit version.

Solutions

1. Set the correct game version in the HMCL instance settings before exporting
2. Restore the instance's versions/<version>/version.json metadata
3. Reinstall the game files for the instance, then retry the export

Example fix

// before
GameVersionNumber version = instance.getVersion(); // unknown() -> IOException
// after
// configure instance game version (e.g. 1.20.1) in HMCL settings
GameVersionNumber version = instance.getVersion(); // resolves
zip.putDirectory(...); // export proceeds

if (instance.getVersion() == GameVersionNumber.unknown()) throw new IOException("Cannot parse the version of " + instanceId);

boolean exportable(DefaultGameRepository repo, String id) { return repo.getGameVersion(id).isPresent(); }

try { exportTask.execute(); } catch (IOException e) { /* fix instance version then retry */ }

When it happens

Trigger: Calling MultiMCModpackExportTask.execute() on an instance whose version metadata is missing or unparseable.

Common situations: Exporting broken or hand-built instances; instances whose version.json was deleted; instances installed from non-standard sources.

Understand the failure class

Background: "is required", "must be set", "missing required field": configuration validation errors across open-source libraries — this error's family across 36 libraries.

Related errors

• Cannot parse the version of
• mmc-pack.json malformed.
• Theme-pack asset source is not a regular file:
• Asset index file malformed
• Bad exit code

AI-assisted analysis of HMCL-dev/HMCL@24702dc5a0 (2026-09-10). Data as JSON: /api/errors/4bc164e7e3e3665a. Report an issue: GitHub.

Appendix: source

Thrown at HMCLCore/src/main/java/org/jackhuang/hmcl/modpack/multimc/MultiMCModpackExportTask.java:93

                }
            }
        });
    }

    /// {@inheritDoc}
    @Override
    public void execute() throws Exception {
        var instanceId = instance.getId();
        ArrayList<String> blackList = new ArrayList<>(ModAdviser.MODPACK_BLACK_LIST);
        blackList.add(instanceId + ".jar");
        blackList.add(instanceId + ".json");
        LOG.info("Compressing game files without some files in blacklist, including files or directories: usernamecache.json, asm, logs, backups, versions, assets, usercache.json, libraries, crash-reports, launcher_profiles.json, NVIDIA, TCNodeTracker");
        try (Zipper zip = new Zipper(output)) {
            zip.putDirectory(instance.getRunDirectory(), ".minecraft", path -> Modpack.acceptFile(path, blackList, whitelist));

            GameVersionNumber version = instance.getVersion();
            if (version == GameVersionNumber.unknown()) {
                throw new IOException("Cannot parse the version of " + instanceId);
            }
            String gameVersion = version.toString();
            GameComponentAnalyzer analyzer = instance.getAnalyzer();
            List<MultiMCManifest.MultiMCManifestComponent> components = new ArrayList<>();
            components.add(new MultiMCManifest.MultiMCManifestComponent(true, false, MultiMCComponents.getComponent(GameComponentType.GAME), gameVersion));

            for (Map.Entry<String, GameComponentType> pair : MultiMCComponents.getPairs()) {
                if (pair.getValue().isModLoader()) {
                    String componentVersion = analyzer.getVersion(pair.getValue());
                    if (componentVersion != null) {
                        components.add(new MultiMCManifest.MultiMCManifestComponent(false, false, pair.getKey(), componentVersion));
                    }
                }
            }

            MultiMCManifest mmcPack = new MultiMCManifest(1, components);
            zip.putTextFile(JsonUtils.GSON.toJson(mmcPack), "mmc-pack.json");

View on GitHub (pinned to 24702dc5a0)