Hi community,

my first post here and really hope you can help me out pointing me in the right direction ;)

In our Umbraco system version 7.1.0 we are experiencing a lot of occurences of a problem of the same type. Many nodes show us in the "Properties Tab" in the field "Link to the document" the error:

(We have a german system so I translate this message freely) "Ups! This document is published but cannot be found in the internal cache. System failure"

If we look in the logs, there are plenty of different errors shown. I am pasting some of them here to give you an idea:

        2015-11-17 08:57:54,672 [9] WARN  Umbraco.Web.Dictionary.DefaultCultureDictionary - [Thread 32] Error returning dictionary item 'Key Account'. Exception: System.ArgumentException: No key Key Account exists in dictionary
       at umbraco.cms.businesslogic.Dictionary.DictionaryItem..ctor(String key)

        2015-11-17 11:23:08,112 [9] WARN  Umbraco.Web.Routing.DefaultUrlProvider - [Thread 29] Couldn't find any page with nodeId=4053. This is most likely caused by the page not being published.
        2015-11-17 11:23:17,953 [9] WARN  Umbraco.Web.Routing.DefaultUrlProvider - [Thread 25] Couldn't find any page with nodeId=1053. This is most likely caused by the page not being published.
        2015-11-17 11:24:41,316 [9] WARN  Umbraco.Web.Routing.DefaultUrlProvider - [Thread 29] Couldn't find any page with nodeId=1184. This is most likely caused by the page not being published.

2015-11-17 11:45:45,462 [9] WARN  Umbraco.Web.Dictionary.DefaultCultureDictionary - [Thread 10] Error returning dictionary item 'Formular'. Exception: System.ArgumentException: No key Formular exists in dictionary
   at umbraco.cms.businesslogic.Dictionary.DictionaryItem..ctor(String key)
   at Umbraco.Web.Dictionary.DefaultCultureDictionary.get_Item(String key)
2015-11-17 11:45:45,489 [9] WARN  Umbraco.Web.Dictionary.DefaultCultureDictionary - [Thread 10] Error returning dictionary item 'Key Account'. Exception: System.ArgumentException: No key Key Account exists in dictionary
   at umbraco.cms.businesslogic.Dictionary.DictionaryItem..ctor(String key)
   at Umbraco.Web.Dictionary.DefaultCultureDictionary.get_Item(String key)
2015-11-17 11:48:10,162 [9] WARN  Umbraco.Web.Dictionary.DefaultCultureDictionary - [Thread 25] Error returning dictionary item 'Formular'. Exception: System.ArgumentException: No key Formular exists in dictionary
   at umbraco.cms.businesslogic.Dictionary.DictionaryItem..ctor(String key)
   at Umbraco.Web.Dictionary.DefaultCultureDictionary.get_Item(String key)
2015-11-17 11:48:10,165 [9] WARN  Umbraco.Web.Dictionary.DefaultCultureDictionary - [Thread 25] Error returning dictionary item 'Key Account'. Exception: System.ArgumentException: No key Key Account exists in dictionary
   at umbraco.cms.businesslogic.Dictionary.DictionaryItem..ctor(String key)

There are hundrets of these errors in the log files. Has anybody ever experienced this issue or could give me a hint in which direction to search or what do do?

Could a restart of the IIS help? Is there some kind of a reload functionality of Umbraco?

Any help is greatly appreciated!

Thanks in advance Sascha