Troubleshooting
Fix missing mods after MRPack conversion
A converted ZIP can be created even when one or more referenced files are unavailable. Use the failed downloads report to identify the exact path, source, environment, and hashes before adding anything manually.
Why files can be missing
- Browser restriction: the host blocks cross-origin requests.
- Untrusted host: the converter intentionally refuses an unapproved domain.
- Unavailable URL: the referenced version was removed or the link expired.
- Network interruption: the request timed out or the tab lost connectivity.
- Hash mismatch: the downloaded bytes do not match the expected SHA-512 value.
Read the failed downloads report
Each failure contains a destination path, a reason, one or more download URLs,
available hashes, and client or server environment flags. The path is the most important
placement instruction. A file listed as mods/example.jar belongs in
mods; a resource pack or configuration file may belong somewhere else.
{
"path": "mods/example-mod.jar",
"reason": "Failed to fetch",
"downloads": ["https://trusted-source.example/file.jar"],
"env": { "client": "required", "server": "unsupported" }
}
Repair a missing file safely
- Download the failed downloads report from the converter.
- Open the JSON file and work through one failure at a time.
- Note the destination path, Minecraft version, loader, environment, and expected hash.
- Open the listed official source or locate the same project on Modrinth. Avoid unofficial mirrors and generic file-download sites.
- Download the exact version expected by the pack, not simply the newest release.
- Place the file at the report's destination path inside the ZIP or launcher instance.
- Repeat for each required failure, then start the pack and review its log.
What common error reasons mean
Failed to fetch
This usually means the browser could not complete the request. Retry once on a stable connection. If the same host fails again, open the official project page and download the exact version manually.
Untrusted download host
The converter did not contact that domain. This is an intentional security boundary, not proof that the modpack is broken. Verify that the URL belongs to the project author or an official distribution platform before downloading it yourself.
SHA-512 mismatch
Do not add the mismatched file. It may be a different version, a changed upstream file, or a corrupted download. Return to the original pack version and locate a file matching the expected release and hash.
Client and server files are different
The report can include environment flags. A file with server set to
unsupported should not be copied to a dedicated server. Likewise, a server-only
utility may not belong in a client instance. Respect these flags instead of adding every
failed JAR to every environment.
When to retry instead of repairing manually
Retry the conversion when many files fail with the same temporary network error. Repair manually when only a few stable entries fail and their official versions are clear. If the original MRPack no longer points to available files, look for a newer pack release rather than reconstructing a large archive from uncertain sources.