Firefox will close now

[jhaber3]

I've installed Firefox on a new computer with Windows 10. Now, on exiting the program I see a notification on the center of the desktop, beginning "Firefox will close now." It then goes on for at least another sentence, although it flashes by too quickly for me to read it, at least on attempts thus far. Any clue? Is it an error message? Thanks.

[Vitesse]

This old thread from 2013 suggests that message is connected to the Better Privacy extension.

https://support.mozilla.org/en-US/questions/960815

Maybe due to a particularly difficult to remove Flash cookie? In which case I suppose it might also be connected to some other cookie removal extension?

[jhaber3]

I bet that's it. The message that flew by could well have in it "LSO." Must be something odd about Windows 10 that's creating or accepting them.

[John_Ha]

It recently started happening to me too (FF 52.0.1 32 bit). I have Better Privacy installed. I managed to get a screen shot. It says

"Firefox will close now. Please stand by while Better Privacy
checks your hard disk fopr LSO cookies ..."

chrome://bprivacy/content/BetterPrivacy.html says:

BetterPrivacy is a Firefox add-on that is able to delete a special kind of cookies: Local Shared Objects in short LSO's (usually known as Flash-cookies) are placed on your computer by a Flash plug-in.

Why are LSO's harmful?

- they are never expiring - staying on your computer for an unlimited time
- by default they offer a storage of 100 KB (compare: Usual cookies 4 KB)
- browsers are not fully aware of LSOs, LSO's often cannot be displayed or managed by browsers
- via Flash they can access and store highly specific personal and technical information (system, user name, ...)
- ability to send the stored information to the appropriate server, without user's permission
- Flash applications do not need to be visible to the user
- there is no easy way to tell which LSO sites are tracking you
- shared folders allow cross-browser tracking, all browsers use the same LSO folder
- the company doesn't provide a user-friendly way to manage LSO's, in fact it's incredible cumbersome
- many domains and tracking companies make extensive use of LSOs
- LSOs are used to re-create data of deleted traditional cookies

Since Flash is a seperate application, running on your system (not under the hood of Firefox) , there is technically no way to prevent it from storing those LSO's on your disk. However they can be deleted at any time but unfortunately most browsers are unable to display or manage LSO's. BetterPrivacy can help here and offers capabilities to list and manage stored LSO's, up to full automatic cleaning, while allowing to define LSO-removal exclusion rules.

[DanRaisch]

Locking due the age of the original posts.