Aqui está algo para tentar.
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The problem is in opening an Office document which is saved in
SharePoint 2010:
When a user has a "read" permission only to a specific document in a
document library, but do not have any permissions in the document
library level nor the site level.
When he is accessing the document,
he receives the "Download File" message with "Open" / "Save" /
"Cancel" options.
When clicking "Open", he is prompted with a user &
password message. When clicking his correct user and password, the
user & password message remains – nothing happens.
Only when clicking
"Cancel" in the user & password message, the document opens.
Users who has read permissions in the document library level or the site
level – manage to open the document successfully, meaning are not
prompted with the user & password message after clicking "Open"
(it opens the document).
Existem 3 maneiras possíveis de resolver este problema:
1. Adicione permissão somente leitura na raiz do conjunto de sites.
2. Desativar o recurso "ViewFormPagesLockDown":
stsadm -o deactivatefeature -url http://SERVERNAME/sites/SITENAME -filename ViewFormPagesLockDown\feature.xml
3. Execute o script a seguir no seu conjunto de sites, isso adicionará o nível de permissão ao nível de permissão de "Acesso Limitado" que você tem nesse conjunto de sites.