I did a web search. Found several listings but none of them told what the file was for. One link reported it as a PUP (Possible Unwanted Program).

Open your file manager to your user account. In the search box, enter 972ce4c6-7e08-4474 and wait. Anything that matches the Full file name, rename it by add .old to it. Then start Firefox. Any problems?

Thanks for your help, I search but didn't find any files.

But I try to deactivate ad-on to test something. It appear that if I deactivate ghostery and remove the file in the history it didn't appear again. So the entry may be linked to ghostery. What is it I still don't know.

Contact ghostly support and ask questions.

Hi - I have the same problem as the initial poster, with the following exceptions:

1) My respawning object is

moz-extension://8c0aa021-d4a2-4d36-8a55-6e1123eaff66/_blank.html

2) I've tried disabling Ghostery and the problem continues.

I emailed Ghostery support over the weekend and they responded today. They say the problem is a Firefox quirk.

Dystopian_Refugee Yours is not the same. Check the code numbers. Please go to the top of any support.mozilla.org web page and use the Ask A Question link; https://support.mozilla.org/en-US/questions/new This will let us look at your system details. No Personal Information Is Collected.

I'm having the same experience. The recurring history listing is:

moz-extension://effb48dc-0584-5240-9766-4eecbc7a1739/_blank.html

It looks like it appears after I have cleared all my history, as others have noted.

I also have Ghostery. I am on a MacBook Pro, OSX 10.9.5 Using Firefox 49.0.1

Steve

X-ray Guy Your code number are also different. Please go to the top of any support.mozilla.org web page and use the Ask A Question link; https://support.mozilla.org/en-US/questions/new This will let us look at your system details. No Personal Information Is Collected.

I've called for more help

Sorry not an answer just a few comments, and potentially a partial explanation. This is not something I have knowledge of, although I will be interested in the correct explanation.

It looks like a script or extension is involved in messaging. I do not see similar entries in my Firefox History so it could be an extension I do not use, or a Firefox feature I do not use such as maybe the Tiles page of newtab, Sync, or even the home page. Although those are just blind guesses.

I do note in this article* mentions "internal-id" so I am not sure whether having a different UUID type string necessarily means these entries are unrelated, and also whether this is an easily identifiable UUID.

Some of these strings may resemble

{972ce4c6-7e08-4474-a285-3208198ce6fd} 
(default Firefox theme)

Fred do you see anything similar in your own History ?

Anyone seeing this, does it stop if you

• use Firefox in its safe mode ?
  Diagnose Firefox issues using Troubleshoot Mode

urielventis I think we can be fairly certain in your case it is related to use of Ghostery.

* Note I found this article

• MDN runtime.MessageSender
  https://developer.mozilla.org/Add-ons/WebExtensions/API/runtime/MessageSender

  If the sender is a background script  and you haven't included a background page, 
it will be "moz-extension://<extension-internal-id>/_blank.html".

I wonder if the reason the History item is apparently undeletable is simply because the event is fired on every restart of Firefox so it is always present in your History.

The only things I found were links to the support pages and the searches I did on the issue.