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[Solved] Simulator detected but not connecting

donmacq · 2026-04-07T17:50:32Z

FSUIPC7, 7.5.6 with MSFS2020 installed via Steam. I selected the FSUIPC startup option of using exe.xml. Started MSFS, and I see FSUIPC icon appear in taskbar. Open it up, see "Simulator detected" and wait for it to try to connect. I waited for a few minutes with no change, exited out of FSUIPC. Restarted FSUIPC (with MSFS still running, at the main menu). Left it for a few minutes and exited. I've read the FAQ entry on adjusting the .ini file entries, but that seems to suppose that (1) FSUIPC is started by MSFS and (2) it eventually connects successfully. Attaching the 2 log files ("_prev" is the first run started via exe.xml)

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Posts: 251

FSUIPC

Admin

April 8, 2026 1:56 pm

(@fsuipc)

Joined: 9 months ago

Posted by: @donmacq
↑
Is it using sockets or named pipes? Could this be a firewall issue?

It is just using the MSFS SDK to connect, which will use whatever underlying protocol that uses for inter-process communication. The firewall will not be an issue.

Can you add:

TestOptions=x800

to the [General] section of your FSUIPC7.ini. Then start MSFS and let that start FSUIPC7 as normal. Then, once MSFS has arrived at the main menu, wait a few seconds then exit FSUIPC7 and show me the FSUIPC7.log file.

Posts: 8

donmacq

Registered

Topic starter

April 8, 2026 2:17 pm

(@donmacq)

Joined: 6 days ago

Here you go. I see "Failed on SimConnect_Open, return = 0x80004005L" in the log.

Attachment : FSUIPC7.log

Posts: 8

donmacq

Registered

Topic starter

April 8, 2026 3:02 pm

(@donmacq)

Joined: 6 days ago

FYI, I did some of the troubleshooting associated with that error code: ran sfc /scannow, deleted temp files, and tried running both the sim and fsuipc as admin. No luck.

Posts: 251

FSUIPC

Admin

April 8, 2026 4:08 pm

(@fsuipc)

Joined: 9 months ago

That error code indicates that there is a permissions problem somewhere. Did you run the FSUIPC7 installer as Admin? If so, uninstall and re-run with standard permissions.

Maybe try installing FSUIPC7 on a different drive, other than d, to see if it is a permission issue with that drive.

Other than that, I cannot advise on this issue. There is something fundamentally amiss/wrong in your Windows installation. Can you run any other MSFS external add-on that uses SimConnect? I suspect not...

Windows permission issue are an ongoing problem, and seem to get worse on each windows update. These seem to affect users with non-standard windows installations, but I am no expert in such things and rely on google for such issues...

Sorry I can't be of more help here, but I am not sure what, if anything, I can do if you are getting that error. You need to check your system and google for possible issues, as you seem to be doing...

John

Posts: 8

donmacq

Registered

Topic starter

April 8, 2026 9:47 pm

(@donmacq)

Joined: 6 days ago

Thanks, John. I've tried reinstalling to C:, no joy. And I've tried all combinations of running MSFS and FSUIPC as Admin and as a regular user. That particular error code is unhelpful. I'm betting it's either a SxS issue or corrupt system file. I'll tinker a bit more.

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