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[Closed] "another instance of Firefox is already running" but it isn't

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sortableapps
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[Closed] "another instance of Firefox is already running" but it isn't

Running Firefox Portable 84.01 on a Windows 10 machine.

Suddenly yesterday, when launching Firefox Portable, I receive the error: "Another instance of Firefox is already running. Please close other instances of Firefox before launching Mozilla Firefox, Portable Edition."

Things I have tried to resolve the issue:
1. Restarting the computer numerous times.
2. Reviewing Task Manager closely and ensuring no Firefox or related tasks are running.
3. Installing fresh instances of Firefox Portable to see if they will run (but they give the same error).
4. Launching standard Firefox to ensure it can run and be closed. (It does.)
4. Placing FirefoxPortable.ini in root of Firefox Portable with AllowMultipleInstances=true. (This works, but then system-launched links try to open a new instance. See https://portableapps.com/node/60315)

There is absolutely no instance of Firefox running, but FirefoxPortable simply will not start. I am assuming there is a flag in a file or the registry somewhere that Firefox Portable is checking that is causing startup to fail, but not sure where to look. Would love some help.

Thanks in advance.

John T. Haller
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Can't Reproduce, Older Version?

I can't reproduce this. Please try Firefox Portable 84.0 to see if it also occurs on your particular machine.

Sometimes, the impossible can become possible, if you're awesome!

sortableapps
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confirmed, same issue in 84.0

John, thanks for the quick reply.

Confirmed same issue in Firefox Portable 84.0.

sortableapps
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Any further thoughts on

Any further thoughts on troubleshooting? Not sure how to proceed to resolve this issue.

John T. Haller
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PC Issue

Unfortunately no. You could try some older versions of Firefox Portable to see if they don't have it on the off chance it's a launcher issue, but the way the launcher works is that error occurs as the launcher does a CreateToolhelp32Snapshot and the enumerates with Process32FirstW until it finds the running process. If Windows is telling the launcher that the process exists, then something is wrong. Did you get a virus infection or corruption recently?

Sometimes, the impossible can become possible, if you're awesome!

BaobobMiller
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I have experienced something similar to this...

I had an issue where after a shutdown glitch in which RocketDock was still apparently in the process of shutting down when the portableAppsPlatform finished closing completely. From that moment on I could run any copy of RocketDock . Upon launching the portableAppsPlatform when it tried to run RocketDock on startup I got an error message that told me another RocketDock was still shutting down, even after a fresh computer reboot. The same message was triggered (presumably by the launcher) any time the launcher for the app was run.

Removing RocketDock and reinstalling it had no effect.
Neither did trying to run a different installation of RocketDock.
There were no open processes associated with either PortableApps or RocketDock with PA closed.
There were no open processes associated with RocketDock with PA open.
Deleting the PortableApps.com directory and replacing it worked.

I don't know if these two things are related at all, it sounds like the error message might have been a little different. but I was unsure weather or not that may be language-pack related or perhaps even a case of not quite remembering what the exact wording of the error message was (like I don't in my case)

I make sure I do the checking to make sure the apps are all closed myself now before shutting down the platform.
(because hiccups happen)

I hope I didn't confuse the issue further.

Baobob Miller

sortableapps
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resolved + thank you

@BaobobMiller, thank you for the detailed thoughts on the issue - much appreciated.
And thank you, @John T. Haller, for your assistance as well.

This issue continued to recur for many work sessions, through computer reboots.

However, after running the latest Windows updates, I can confirm that the issue has resolved. I performed no other corrective action than running the Windows updates, so it seems this fixed whatever the underlying problem was.

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