Find or recover your FSUIPC registration key, locate FSUIPC7.key, fix rejected licence details and learn whether an older key will work.
Your FSUIPC registration key is usually in the original purchase email or the seller account’s order history. On a registered Windows PC, search the active FSUIPC installation folder for FSUIPC*.key. Keep the registered name and email address with the key: all three must match. Free, unregistered FSUIPC needs no key.
This applies to FSUIPC generations used with Flight Simulator 2004, FSX and FSX: Steam Edition, Prepar3D, Microsoft Flight Simulator 2020 and Microsoft Flight Simulator 2024 on Windows PC. FSUIPC is a Windows desktop module or application; it cannot be installed in the Xbox or PlayStation console editions of the simulators.
How do I recover a lost FSUIPC key or serial number?
- Identify the FSUIPC generation. Establish whether the purchase was for FSUIPC3, FSUIPC4, FSUIPC5, FSUIPC6 or FSUIPC7. A seller may describe the same credential as a registration key, licence key or serial number.
- Search every relevant email account. Look for “FSUIPC”, “registration”, “licence”, “serial” and the original order receipt. Retain the purchaser name and registered email or address line as well as the key; entering only the key is often insufficient.
- Check the seller account. Sign in to the account used for the purchase and inspect its orders, licence details, invoices and archived downloads. Downloading the free installer again will not reveal or create a paid registration.
- Search the old Windows installation. In File Explorer, search the simulator and FSUIPC folders for
FSUIPC*.key. Copy any result to a private backup before uninstalling FSUIPC, deleting the simulator or replacing the computer. - Request order recovery from the original seller. Supply the order number, purchaser name, original email address, approximate purchase date and FSUIPC generation. Do not buy another licence until the old order has been checked.
Where is the FSUIPC key file stored?
The key file is normally beside the active FSUIPC module or executable, but its name and location depend on the generation and installation method.
| Simulator and FSUIPC generation | Typical place to inspect | Key filename |
|---|---|---|
| Flight Simulator 2004 with FSUIPC3 | The simulator’s Modules folder | FSUIPC.key |
| FSX or FSX: Steam Edition with FSUIPC4 | The simulator’s Modules folder | FSUIPC4.key |
| Prepar3D with FSUIPC5 or FSUIPC6 | The active FSUIPC installation or add-on folder selected during setup | FSUIPC5.key or FSUIPC6.key |
| Microsoft Flight Simulator 2020 or 2024 with FSUIPC7 | The separate FSUIPC7 installation folder | FSUIPC7.key |
Custom installation folders and retained copies from older installations can change what Windows finds. The decisive file is the one beside the FSUIPC copy that actually launches. Files ending in .ini hold settings and .log files hold diagnostic output; neither replaces the .key file.
Where is my FSUIPC7 key?
Your FSUIPC7 registration is stored in FSUIPC7.key in the folder containing the active FSUIPC7 executable. FSUIPC7 is a separate Windows application, so do not look for its key among aircraft packages in the simulator’s Community folder.
If several FSUIPC7 folders exist, inspect the target of the shortcut used to start it. Preserve the key before updating or reinstalling; our FSUIPC7 installation and reinstall procedure explains which registration-related files should be retained.
Can I copy the key file to another installation?
You can normally restore an unchanged key file to the active folder for the same licensed FSUIPC generation. Close FSUIPC first, keep a backup, and do not rename an older generation’s key in an attempt to convert it.
The files are generally readable in a plain-text editor, but edit a copy rather than the only original. Never publish the registered identity or key. If Windows hides extensions, confirm that the filename ends in .key, not .key.txt.
Why is my FSUIPC registration key rejected?
A rejected key usually means that the FSUIPC generation, registered identity or licence type does not match the original purchase.
- Wrong major generation: an FSUIPC4 key does not become an FSUIPC7 key by changing the filename. Install the generation named in the purchase record or obtain the correct entitlement.
- Name or address mismatch: enter the purchaser name and original email or address exactly as issued, including punctuation, spacing and capitalisation. Do not substitute a newer email address.
- Wrong licence field: a WideFS key is separate from the FSUIPC registration key and cannot be entered in its place.
- Copy-and-paste damage: exclude labels, quotation marks, line breaks and leading or trailing spaces while leaving the actual key unchanged.
- Wrong installation folder: an obsolete copy of FSUIPC may be receiving the key while the simulator launches a different copy.
- Damaged key file: restore the untouched backup rather than manually reconstructing the file. FS2004 users can follow our FSUIPC.key error checks for FS2004 when the module reports invalid or mismatched registration details.
Will an old FSUIPC key work with a newer version?
An old key normally remains valid for maintenance releases within the same named FSUIPC generation, but it should not be assumed to activate a later major generation. For example, ownership of FSUIPC4 does not by itself establish an entitlement to FSUIPC7.
Some purchases, bundles or upgrade arrangements may cover more than one named product. The original receipt and the licences shown in the seller account are the deciding records. Our FSUIPC package and registration documentation for FSUIPC4 through FSUIPC7 can help identify the correct installer and the distinction between free and registered operation.
Can I get a free FSUIPC key?
There is no legitimate universal FSUIPC registration key, and a key belonging to another user will not match your registered identity. The unregistered edition itself is free and does not require a serial number.
Unregistered FSUIPC can provide the interface required by many aircraft and utilities. Registration unlocks the paid user facilities belonging to that generation, such as its advanced control assignment and calibration functions. If an add-on merely says that it requires FSUIPC, that does not automatically mean you must buy or enter a key.
Is the FSUIPC serial number the same as the simulator product key?
No. An FSUIPC registration key licenses FSUIPC and is separate from the activation code, digital entitlement or serial number for the flight simulator itself. If the missing code is for Flight Simulator X rather than FSUIPC, use our FSX product-key recovery steps.