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ISSUERSI LauncherInstallationError 5021Windows 11

RSI Launcher install fails with Error 5021 (Installer Error)

Tracked since 23 Sept 2026 · Last researched 23 Sept 2026

Problem

Your Star Citizen install fails in the RSI Launcher with Error 5021, shown as Installer Error.

CIG hasn't pinned down every cause yet, but it thinks the likely culprit is how Windows 11 handles drive sector sizes on some drives. RSI still lists the error, and a fix for it, on its support site.

Applies to Alpha 4.10.1 LIVE (RSI Launcher 2.17) · Current

Best current action

Run CIG's registry fix, restart your PC, and install again

Start with the registry command CIG gives for Error 5021: run it from an administrator Command Prompt, restart your PC, then try the install again. It's the only fix RSI lists for this code, and CIG says it has worked for some players, not all. If you'd like to see whether your drive is the kind it changes, check the sector size with fsutil first. Still stuck? Work through RSI's general launcher steps: restart the launcher, verify files, and as a last resort, do a clean reinstall.

CIG thinks Error 5021 most likely comes from Windows 11 reporting a drive sector size larger than 4 KB. This command makes Windows present 4 KB sectors instead.

What to do

  1. Open the Windows Start menu, search for Command Prompt, right-click it, and select Run as administrator.
  2. Enter: REG ADD "HKLM\SYSTEM\CurrentControlSet\Services\stornvme\Parameters\Device" /v "ForcedPhysicalSectorSizeInBytes" /t REG_MULTI_SZ /d "* 4095" /f
  3. Restart the computer.
  4. Open the RSI Launcher and try the installation again.

You'll need administrator rights on the PC, and the change does nothing until you restart. Copy the command exactly. RSI warns that registry edits can cause serious problems if you get them wrong, and neither RSI nor Microsoft gives an undo step here, so the setting stays after the restart. It only applies to drives that use Windows' built-in NVMe driver.

Limited SupportLow To Medium riskRSI's current Error 5021 guidance, with no success rate or affected launcher version.

Diagnostic checks

These checks can identify the affected state, but they are not fixes.

Check your install drive's sector size

It's a quick, read-only way to see whether your drive reports sectors larger than 4 KB, which is what the registry fix changes. A normal result doesn't rule the drive out, though.

What to check

  1. Open Command Prompt as administrator.
  2. Run fsutil fsinfo sectorinfo followed by the drive letter of the install drive, for example: fsutil fsinfo sectorinfo C:
  3. Read the PhysicalBytesPerSectorForAtomicity and PhysicalBytesPerSectorForPerformance values; values above 4096 mean the drive reports a sector size larger than 4 KB.

This only reads drive information; nothing changes.

Limited SupportLow riskMicrosoft's Windows 11 guidance for the same registry setting; it isn't specific to Star Citizen.

Other options

Fully restart the RSI Launcher

It's RSI's first suggestion for any 50XX launcher error and only takes a minute, though RSI doesn't tie it to Error 5021 specifically.

Steps

  1. Fully exit Star Citizen and the RSI Launcher.
  2. Check the system tray; if more than one launcher instance is shown, right-click the extra one and end it.
  3. Restart the RSI Launcher, log in, and check whether the error returns.

Nothing gets changed or deleted.

Limited SupportLow riskRSI's current general guidance for 50XX launcher errors.

Verify the game files

RSI says bad or corrupted game files can cause 50XX errors, and Verify swaps them for good copies. Like the restart, it's general launcher advice rather than a 5021 fix.

Steps

  1. Open and log in to the RSI Launcher and go to Settings.
  2. Select the channel that shows the error, such as LIVE or PTU.
  3. Make sure the game install location matches where the game is installed.
  4. Click VERIFY and let it finish re-downloading any needed files.

This only helps if the launcher's install location is set to your actual game folder. Verify may re-download files, so give it time to finish.

Limited SupportLow riskRSI's current general guidance for 50XX launcher errors.

Do a clean reinstall as a last resort

When verifying doesn't help, RSI's last general step for 50XX errors is to remove everything and start from a clean slate.

Steps

  1. Uninstall the RSI Launcher and Star Citizen.
  2. Delete the remaining launcher and game files.
  3. Install the RSI Launcher again and reinstall Star Citizen.

Everything is deleted, so you'll download the whole game again.

Limited SupportLow To Medium riskRSI's current general guidance for 50XX launcher errors.

Related

Build status

RSI's support site still lists Error 5021 and its registry fix, without naming a specific launcher or game version.

Alpha 4.10.1 · Known Issue Continues · LIVE

Boundaries and evidence

This page is only for Error 5021. Error 5014, a launcher stuck on Checking for Updates with no error, and connection errors once the game is running need different fixes.

RSI doesn't say which launcher version or Star Citizen patch is affected, or how often the registry fix works.

How often any of these steps clears Error 5021 is unknown; no recent player results are available.

Microsoft wrote its sector-size guidance for other software. The link to Error 5021 is that CIG uses the same registry setting.

You'll see other advice online, like running the launcher as administrator, moving the install folder, or clearing the launcher cache. None of it has a documented result for this error, so it isn't included here.

Seeing a different code during install or verify? Our page on RSI Launcher Error 5014 covers that one.

If the launcher never shows an error at all, see our page on the launcher stuck on Checking for Updates.

Data sources

RSI Support · Specialist Community