Do not save captchas to disk or share them between tabs. They are too short-lived to be worth it now. This should reduce associated I/O errors.

src/Posting/Captcha.cache.coffee

@@ -1,9 +1,5 @@
 Captcha.cache =
   init: ->
-    $.get 'captchas', [], ({captchas}) =>
-      @sync captchas
-      @clear()
-    $.sync 'captchas', @sync.bind(@)
     $.on d, 'SaveCaptcha', (e) =>
       @save e.detail
 
@@ -19,38 +15,28 @@ Captcha.cache =
       QR.posts.length > 1 or Conf['Auto-load captcha'] or QR.posts[0].com or QR.posts[0].file
     )
 
-  sync: (captchas=[]) ->
-    captchas = [] unless captchas instanceof Array
-    @captchas = captchas
-    @count()
-
   getOne: (isReply) ->
     @clear()
     i = @captchas.findIndex((x) -> isReply or !x.challenge?)
     if i >= 0
       captcha = @captchas.splice(i, 1)[0]
-      $.set 'captchas', @captchas
       @count()
       captcha
     else
       null
 
   save: (captcha) ->
-    $.forceSync 'captchas'
     @captchas.push captcha
     @captchas.sort (a, b) -> a.timeout - b.timeout
-    $.set 'captchas', @captchas
     @count()
 
   clear: ->
-    $.forceSync 'captchas'
     if @captchas.length
       now = Date.now()
       for captcha, i in @captchas
         break if captcha.timeout > now
       if i
         @captchas = @captchas[i..]
-        $.set 'captchas', @captchas
         @count()
 
   count: ->

src/platform/$.coffee

@@ -664,7 +664,7 @@ else
     # XXX https://github.com/greasemonkey/greasemonkey/issues/2033
     # Also support case where GM_listValues is not defined.
     $.delete Object.keys(Conf)
-    $.delete ['previousversion', 'QR Size', 'captchas', 'QR.persona', 'hiddenPSA']
+    $.delete ['previousversion', 'QR Size', 'QR.persona', 'hiddenPSA']
     try
       $.delete $.listValues().map (key) -> key.replace g.NAMESPACE, ''
     cb?()