Troubleshooting¶

DDMM won't start (Linux)¶

Run DDMM from a terminal to see why. Most often a library is missing, for example error while loading shared libraries: libwebkit2gtk-4.1.so.0 from the .tar.gz when WebKitGTK 4.1 isn't installed. An AppImage window can also stay blank with an EGL_BAD_PARAMETER error. Installing on Linux covers which download to use for your distribution, the exact package to install for each one, AppImage/FUSE errors, and the blank-window workaround.

Windows SmartScreen warns about an unknown publisher¶

Expected for these builds — they aren't code-signed. Click "More info", then "Run anyway". This applies to both the installer and the app itself the first time you run it.

DDMM opens straight to Settings¶

On startup DDMM checks your Game Path; if it's invalid or empty (including on a completely fresh install), it first tries to auto-detect your Helldivers 2 install via Steam and, if that succeeds, fills in and saves the path for you automatically — you'll see a "Found Helldivers 2 at ..." message and DDMM continues straight to Mods, no trip to Settings needed.

You only land on Settings when auto-detection also fails (Steam isn't installed, or the game isn't). Set the path yourself, or click Auto-detect again after installing/moving the game — see First-time setup.

A mod's manifest can't be read¶

DDMM reads each mod's manifest.json when you add the mod and every time it starts. It accepts the usual hand-editing quirks — a UTF-8 byte-order mark, UTF-16 files, // comments, trailing commas, GUID/iconPath style key spellings, "Version": "1", a missing Description, Manifest.json instead of manifest.json, and Windows \ paths. When a manifest still can't be read, the error names the mod and, for a JSON syntax error, the line and column, e.g.

Couldn't install "Some Mod.zip".
Step: reading its manifest.json
Cause: manifest.json is not valid JSON: expected ',' or '}' at line 4 column 5
Hint: The mod's manifest.json is broken: let the mod's author know. ...

If that happens while adding a mod, the mod isn't installed; the popup and the log show the reason. Report it to the mod's author (and to us, see Reporting bugs, if you think DDMM should accept it).

If an already-installed mod's manifest becomes unreadable (e.g. you edited it by hand), DDMM skips just that mod when loading the list and logs Skipping mod in "...": <reason> — the rest of your mods still load. Fix or re-download that mod: click Open Folder next to Data Folder in Settings, go into mods/, and fix or delete its folder.

A mod won't install¶

When adding a mod fails, the popup (and the log) says which file, which step failed (downloading it, opening the archive, reading its manifest.json, extracting it, copying its files, ...), why in plain words, and what to do about it:

Couldn't install "koyuki launcher.zip".
Step: opening the archive
Cause: the zip archive is incomplete or damaged: its table of contents (at the end of the file) is missing, which
usually means the download didn't finish (invalid Zip archive: Could not find EOCD)
Hint: Download the mod again and add the new file. ...

The text in parentheses is the archive tool's own message; include it if you report a bug. Common causes:

The download didn't finish, or the site sent a web page (a login or "please wait" page) instead of the file. Download it again from the mod's page.
Password-protected archives, archives split into parts (.7z.001, .z01, .part2.rar missing) and 7z archives packed with Deflate64 can't be installed directly. Extract them yourself (for example with 7-Zip), then add the extracted folder with Add Folder.
Two mods with the same ID. Some authors copy one mod's manifest.json into their next mod, so both claim the same GUID. DDMM names the mod already using it. Tell the author; to install it anyway, extract the archive, delete its manifest.json, and add the folder with Add Folder (DDMM then gives it an ID of its own).
An archive of archives (one zip per variant inside the download) installs with a warning that names the inner archives. Extract the one you want and add that instead.

DDMM opens a zip, 7z or RAR by what's inside, not by its name, so a RAR uploaded as .zip installs fine.

A mod I added doesn't show up¶

A mod folder under mods/ with no manifest.json in it at all is silently skipped when DDMM loads the mod list (rather than erroring) — this can happen if an install was interrupted. Delete the incomplete folder and re-add the mod.
Check the log file — a failed add shows a popup with the specific error, and the same detail is in the log.

My mods folder filled the disk with nested copies of itself¶

Versions up to and including 2.0.0-rc.6 had a bug: using Add Folder (or dragging a folder in) on DDMM's own mods/ folder, or on a folder that contains it, made DDMM copy that folder into itself. The copy kept reading what it had just written, so it nested a full copy of every mod inside the previous copy, over and over, until the path got too long or the disk filled up. A 1 GB mod folder can end up taking hundreds of GB. This is most likely when DDMM runs portable next to an existing mods/ folder and you point Add Folder at that folder. Newer versions refuse to do this (see Add Folder).

The duplicates all live under one extra folder, directly inside mods/, that is named after the folder you picked:

You picked mods/ itself: the extra folder is mods/mods/, and inside it is mods/mods/mods/, and so on. Each level holds another copy of all your mods.
You picked a folder that contains mods/, say MyMods/: the extra folder is mods/MyMods/, and the nesting goes mods/MyMods/mods/MyMods/....

Your real mods are the other folders directly inside mods/. They were only ever read, never changed. To clean up:

Close DDMM and update it to a version with the fix.
Find the data folder: Open Folder next to Data Folder in Settings, then go into mods/.
Look inside the extra folder (mods/mods/ or mods/<name you picked>/) and check that it only holds copies of mods you still have directly in mods/. If you really had a mod of your own named mods, only its own files at the top of that folder are real. The copies start one level down.
Delete that one extra folder. Don't delete anything else. It can be too deep for File Explorer ("path too long"), and too big for the Recycle Bin, so use a terminal:
- Windows (Command Prompt, not PowerShell). The \\?\ prefix lets it remove very long paths: rmdir /s /q "\\?\C:\full\path\to\mods\mods". If that still fails, mirror an empty folder over it first, then remove both: mkdir "%TEMP%\empty", then robocopy "%TEMP%\empty" "C:\full\path\to\mods\mods" /MIR, then rmdir /s /q "\\?\C:\full\path\to\mods\mods" and rmdir "%TEMP%\empty".
- Linux: rm -rf -- "/full/path/to/mods/mods".
Start DDMM. Mods directly in mods/ that have a manifest.json show up as before. For any that don't, use Add Folder on that mod's own folder: DDMM adds it where it is, without copying it.

Deploy or Purge fails immediately¶

Both refuse to run against an invalid Game Path — double-check Settings first. If the path is valid but deploy still fails partway through, check the log for which file operation failed (for example, a patch file the mod claims to include that doesn't actually exist in its folder).

A specific mod won't deploy, or deploying it errors out¶

V1 and V2 manifests deploy the same way. If an enabled option (or the selected sub-option) doesn't actually contribute any files, check the log file for a warning naming the mod and an out-of-range option/ sub-option index, or an Include folder that doesn't exist in the mod's own directory — deploy skips that option rather than failing the whole deploy, but it also means nothing gets installed for it.

Browser handoff fails immediately with a Downloads-folder error¶

"the downloads folder isn't set or doesn't exist -- check it in Settings" means your Downloads Folder setting is empty or points at a folder that no longer exists — fix it in Settings, then retry.

"a handoff is already in progress"¶

Only one browser handoff can run at a time. Cancel or wait for the current one (Waiting/Installing popup) to finish before starting another.

Closing DDMM says "Saving profiles..." but the window never closes¶

Fixed in rc.4 — a missing window permission meant the app could save your profiles and then silently fail to actually close itself afterward, leaving the window stuck open with no visible error. If you're still on rc.3 or earlier, update DDMM. On a version with the fix, closing that still doesn't finish within a few seconds instead shows a "Couldn't save profiles" or "Deploy in progress" prompt asking whether to close anyway — check the log file for the underlying error if that keeps happening.

Linux (CachyOS, Arch, Steam Deck, and others)¶

For installing DDMM itself (which file, dependencies, AppImage, blank window), see Installing on Linux. This section covers problems once DDMM is running.

"Game path is invalid!" even though the path is right¶

Fixed in 2.0.0-rc.6. Earlier versions checked the path in a way that could never see inside hidden folders on Linux — and the default Steam library is under ~/.local/share/Steam (or ~/.steam/steam), so every default install was rejected. Update DDMM. On a fixed version, the message under the field says exactly what's wrong (see First-time setup).

Where the game usually is:

Steam install	Game Path
Native package (`steam` from pacman/CachyOS, Debian, ...)	`~/.local/share/Steam/steamapps/common/Helldivers 2`
Flatpak (`com.valvesoftware.Steam`)	`~/.var/app/com.valvesoftware.Steam/.local/share/Steam/steamapps/common/Helldivers 2`
Snap	`~/snap/steam/common/.local/share/Steam/steamapps/common/Helldivers 2`
Extra library on another drive	`<library>/steamapps/common/Helldivers 2` (see Steam → Settings → Storage)

Auto-detect checks all of the above plus every library listed in Steam's libraryfolders.vdf. Paths with spaces, non-English characters, and symlinked libraries all work. In the folder picker, press Ctrl+H to show hidden folders like .local, or just paste the path into the field (~ isn't expanded — use the full /home/<you>/... form).

DDMM only needs to read and write the game's data/ folder; it doesn't care whether Steam is native or Flatpak, or which Proton version runs the game.

Game on an NTFS or exFAT drive (dual boot)¶

If the drive is mounted read-only — Linux does this to an NTFS volume Windows left "dirty" (Fast Startup or hibernation) — deploying fails with Read-only file system. Disable Fast Startup in Windows, shut Windows down fully, and remount.
The drive must be mounted with your user as owner (the default for drives mounted from your file manager). If deploying fails with Permission denied, check the mount options (uid=/gid= for ntfs3/exfat).
Letter case: NTFS keeps the names Windows created (data, bin, helldivers2.exe), which is what DDMM expects.

Adding a mod fails¶

Every failure now shows the real reason in the popup (older versions only said errors disabled in production.) and writes it to the log. Mods downloaded from a URL are staged in a .downloads folder inside the data folder (not /tmp, which is a small RAM disk on Arch/CachyOS), and DDMM copies instead of moving whenever a file has to cross from one drive to another.

Where the log is on Linux¶

With the .tar.gz, .deb, .rpm or AppImage, the data folder is normally ~/.local/share/io.github.katsyk.ddmm/, so the log is ~/.local/share/io.github.katsyk.ddmm/logs/Democracy Defender Mod Manager.log. Exception: if you extracted the .tar.gz into a folder you can write to that already has DDMM data (mods/, settings.json) or a portable.txt next to the executable, DDMM runs portable and the log is in logs/ next to the executable. The first lines of the log say which one it picked; Open Folder next to Data Folder in Settings always opens the right one. If you moved the data folder, the log is in logs/ inside the folder you chose.

"Data Folder Not Found" when DDMM starts¶

DDMM's data is in a folder you chose, and that folder isn't there: typically a USB or external drive that isn't connected, or a changed drive letter. DDMM hasn't created or deleted anything. Connect the drive and click Retry, or use Locate Folder... to point DDMM at where the data is now. See If the folder is missing at startup.

Running DDMM from a terminal (./ddmm) also prints the log live.

Still stuck?¶

See Reporting bugs.