"Access Denied" when syncronizing offline files

A colleague of mine was complaining that he was experiencing Access Denied message while synchronizing his folder redirected offline files on his Windows 7 laptop machine with enabled option for encrypting the offline files cache. While he was able to successfully synchronize folder redirected offline files on his Windows 8.1 desktop workstation with disabled option for encrypting the offline files cache.
The reason for this strange behavior is that Windows for encrypting the offline files cache is using native EFS. Also, for testing purposes he tried to encrypt some folder on NTFS file system, but he was unable to do that. So, now it was easy to guess that EFS is not working as should. After checking the Data Recovery Agent in Computer Configuration\Windows Settings\Public Key Policies\Encrypting File System in Default Domain GPO, I have noticed that default self signed Administrator certificate for EFS data recovery agent has expired.
Deleting this expired certificate and generating new EFS data recovery certificate and importing it into Default Domain GPO, has solved all the problems. This new Data Recovery Agent certificate can be self signed and can be generated with cipher /r:cert_file_name, or if there is Microsoft CA in organization EFS recovery agent certificate template can be used.
 

Folder redirected offline folders out of sync

A colleague of mine on his Windows 7 client workstation was complaining about his profile redirected offline folders that were out of sync with folders that were residing on file server. He tried almost everything to get those files and folders in sync, so finally last chance to rescue was to reset offline database and re-initialize the cache of offline files.
In order to do that, following registry entry has to be created:

FormatDatabase  DWORD (32 bit value) : 1

in

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\CSC\Parameters

After rebooting the client, redirected offline folders started to work as expected.

Note: Before taking this action please make backup of your files, because unsynchronized changes will be lost.