r2modman not opening: installer and permission checks

Confirm which build and version you installed

When r2modman is not opening, verify the file before assuming a bug. The current release is v3.2.19, published 2026-08-21, and it ships for Windows and Linux only. There is no macOS build in this release, so a similarly named macOS download is a different program with different data. Compare your file against the published size in the download center: r2modman-Setup-3.2.19.exe is 165,156,122 bytes and r2modman-3.2.19.AppImage is 200,488,834 bytes. A truncated or renamed download is a common cause of an installer that appears to do nothing at all, so confirm the build you actually have before troubleshooting anything else.

• v3.2.19 is the current release, published 2026-08-21.
• Windows and Linux only; there is no macOS build in v3.2.19.
• Check the exact file size against the download center listing.

Launch it from a terminal to keep the error visible

A window that never appears usually printed something and then exited. Start the manager from a terminal so that message stays on screen. On Windows, open Command Prompt or PowerShell, change to the folder holding the setup or portable file, and run it by name. On Linux, grant executable permission once and run the AppImage from the terminal. Read the first error line rather than the last, and note whether it names a missing library, a sandbox failure, a permission problem, or a file that no longer exists. A silent return to the prompt within a second or two is itself a finding, because it means the operating system refused to start the process.

chmod +x r2modman-3.2.19.AppImage
./r2modman-3.2.19.AppImage

• Run the executable from Command Prompt or PowerShell on Windows.
• Run the AppImage from a terminal on Linux.
• Note the first error line and the file it names.

Rule out security software

Security tools sometimes quarantine a single file from an Electron application, which leaves a program that starts and dies without a useful dialog. Open Windows Security → Virus & threat protection → Protection history (Win + R, then windowsdefender: is the quickest route), filter on Quarantined items, and look for the manager’s exact filename. Restore it only after confirming its version, size, and SHA-512 value against the published release — a restore puts the file back in its original location, not in Downloads. If the application is blocked rather than quarantined, add an exception for r2modman.exe specifically instead of disabling system-wide protection. A narrow exception for one executable is far easier to review later than a blanket exclusion, and after restoring any file you should launch from the terminal again so the next error stays visible.

• Search the quarantine history for the manager's exact filename.
• Restore only after filename, version, and size match.
• Prefer one application exception over disabling protection.

Electron sandbox failures on Linux

If the manager fails to start on Linux, try the documented --no-sandbox option. Electron applications can be blocked by current AppArmor policy, and the flag is the quickest way to confirm that the sandbox is the cause rather than a missing library. Treat it as a diagnostic: if the application starts with the flag and fails without it, you have found the layer, and the durable fix is to correct the system or package permissions instead of running permanently with a reduced security boundary. Capture the terminal output from both attempts so the difference is documented.

./r2modman-3.2.19.AppImage --no-sandbox

• Compare a normal launch with a --no-sandbox launch.
• A difference confirms the sandbox layer rather than a missing library.
• Fix permissions afterwards instead of keeping the flag forever.

Confirm the app can write to its own folder

If the manager opens only when run as an administrator, the real problem is that a folder it needs is not writable with ordinary permissions. Elevation may get you a window, but it also changes where data is written and makes later path problems harder to reason about. The better fix is to move the application and its data folder somewhere your user account owns, such as a folder under your home directory, and to keep it out of the game installation. Confirm the change by launching normally, without elevation, and completing one Start modded launch.

• Test whether a normal, unelevated launch succeeds.
• Move the application to a location your account owns.
• Keep the application out of the game installation.

Installation Aborted during setup

An Installation Aborted message is a rare, known installer failure rather than a sign that your download is wrong. Uninstall r2modman through the control panel first, because failed installations are sometimes treated as installed. Start regedit and use Edit → Find to search for r2modman. It returns several hits, and only one branch is the installer’s own record: under HKEY_CURRENT_USERSoftwareMicrosoftWindowsCurrentVersionUninstall there is a key named as a {GUID} whose DisplayName reads r2modman. That is the key to delete. This installer is per-user, so nothing of its own sits under HKEY_LOCAL_MACHINE, and keys belonging to a game or another vendor should be left alone. Under C:/Users/<user>/AppData, remove all r2modman references in Roaming and Local, then restart the PC. If it still fails, repeat those steps and run the installer as an administrator, knowing that installing as admin is known to cause separate problems with downloading the Thunderstore mod list.

• Uninstall through the control panel first.
• Delete the Uninstall key whose DisplayName is r2modman, found with regedit → Edit → Find.
• Clear the r2modman folders under %AppData% (Roaming) and %LocalAppData% (Local), then reboot.