Adding Launch Parameters to a Service (Manual Workaround)

Some tools you launch from PERFLIGHT need start-up parameters to run the way you want — for example, GSX/FSDT's updater (Couatl_Updater.exe) run with /SILENT /INSTALLMODE=TRUE so it updates silently.

A proper UI for this is coming in a future release. Until then, you can add parameters by editing PERFLIGHT's database directly using the steps below.

⚠️ Advanced / at your own risk. This edits PERFLIGHT's internal database. Follow the backup step so you can always undo it.

Before you start

• This works for any EXE service you've already added to PERFLIGHT. (It does not apply to web/URL services.)

• You'll need a free tool called DB Browser for SQLite (Windows download).

Step 1 — Close PERFLIGHT

Fully exit the app first. Editing the database while PERFLIGHT is running can cause your changes to be lost.

Step 2 — Back up your database

Your database lives in one of these folders (paste the path into the File Explorer address bar):

• Normal install: %AppData%\com.sim.perflight\

• Beta / dev build: %AppData%\com.sim.perflight.dev\

Inside, find perflight.db and make a copy somewhere safe (e.g. your Desktop). If anything goes wrong, you can restore this copy.

Step 3 — Open the database

1. Open DB Browser for SQLite.

2. Choose Open Database and select your perflight.db.

3. Go to the Execute SQL tab.

Step 4 — (Optional) Find your service's name

If you're not sure exactly what you named the service, run this to list them all:

SELECT custom_name, executable_path FROM user_services; 

Note the custom_name of the service you want to add parameters to.

Step 5 — Add your parameters

Paste this into the Execute SQL tab, adjusting the two highlighted parts, then click Execute (the ▶ play button):

UPDATE user_services SET launch_args = '["/SILENT","/INSTALLMODE=TRUE"]' WHERE custom_name = 'GSX Updater'; 

• Replace 'GSX Updater' with your service's name (from Step 4).

• Replace the parameters with your own. Each parameter is its own piece in quotes, separated by commas, all inside the square brackets:

  • /SILENT /INSTALLMODE=TRUE → ["/SILENT","/INSTALLMODE=TRUE"]

  • A single parameter → ["/SILENT"]

  • A parameter with a value stays together → /INSTALLMODE=TRUE is one piece, not two.

Step 6 — Save and test

1. Click Write Changes (top toolbar) to save.

2. Reopen PERFLIGHT and launch the service.

It will now start with your parameters applied. 🎉

Removing parameters later

To go back to launching with no parameters, run this and Write Changes:

UPDATE user_services SET launch_args = NULL WHERE custom_name = 'GSX Updater'; 

Tips & troubleshooting

• Nothing changed / it errored? Restore your backup copy of perflight.db and try again. Most issues are a typo in the brackets or quotes — make sure brackets are balanced, every parameter is in "double quotes", and there's a comma between each one (no comma after the last).

• Parameter contains a space? Keep it as one quoted piece. Any backslashes in a path must be doubled, e.g. a config path becomes ["--config","C:\\My Folder\\app.cfg"].

• Which folder is mine? If you installed the normal release, use com.sim.perflight. The com.sim.perflight.dev folder only exists for beta/development builds.