This article describes issues you might experience while launching an application or desktop with VDA 7.6 LTSR CU1 installed. You might experience a delay upto 2 minutes at "Waiting for local session manager", however the RDP session works fine.
The following registry tweaks resolves the issue:
1. HKEY_LOCAL_MACHINE\SOFTWARE\Citrix\GroupPolicy
Name: GpoCacheEnabled
Type: REG_DWORD
Value: 1
2. HKEY_LOCAL_MACHINE\SOFTWARE\Citrix\GroupPolicy
Name: CacheGpoExpireInHours
Type: REG_DWORD
Value: 5 to 24
The problem is caused by RSOP calculation and the read logon policies which would cause the latency.
If you enable this policy setting, the Group Policy caches policy information after every background processing session. This cache saves applicable GPOs and the settings contained within them. When Group Policy runs in synchronous foreground mode, it refers to this cache which enables it to run faster
Note: The issue does not happen with VDAs released after LTSR CU1 i.e version 7.7 and so on.