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~ 50% of the open Tabs generate a "File not found" on restart

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since firefox4 (also applicable for firefox 4.01 and 5.0) i get a lot of "file not found" errors when i open firefox and firefox restores the session. with firefox 3.x i don't had this error.

if only ~3 tabs are open, there everything is loaded without problem but most of the time i have >15 tabs in the session and about 50% of them are loaded with the "file not found" error.

i tried some of the solutions i found in the forum:

  • disabled ipv6
  • disabled dns prefetch
  • disabled all plugins/addons (created a new profile)
  • disabled proxy

the firewall is correctly configured, other browsers work without problems (even firefox 3.5).

All Replies (1)

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a solution for me was:

options > advanced > network - override automatic cache management - limit cache to 0 MB of space

it looks like the problem is in the local caching, if the cache is turned on, the browser looks in the disk cache if the file is found, if not it generates an 404 and does not lookup the data on the internet.

after turning off the local disk cache, everything works again.

@mozilla: please add a bugfix