Ok I have the solution:
When using "ApplicationPoolIdentity" with IIS 7.5 the corresponding user is (a virtual system user):
"IIS AppPool<AppPoolName>"
You can grant this user permissions and check security setting by searching for this user. See the full explanation here:
http://www.iis.net/learn/manage/configuring-security/application-pool-identities
2.1m questions
2.1m answers
60 comments
57.0k users