Increase maximum size pst-files

I heard that the default size for pst-files is 20 GB but also that there must be a registry value that allows to increase the maximum up to approximately 4PB (4096TB).
How do I increase the maximum file size of an UNICODE pst file?

In Outlook 2003 and Outlook 2007, the maximum size of a Unicode pst-file has indeed been limited to 20GB. In Outlook 2010 and 2013, this limit has been set to 50GB.
You can increase (but also decrease) this limit via the Registry or via Group Policies.
Note: This tip does not apply to pst-files who are in the Outlook 97-2002 format (ANSI formatted pst-files).

Via the Registry

 You need to go to the following location in the Registry;

• Outlook 2003
  HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\Outlook\PST
• Outlook 2007
  HKEY_CURRENT_USER\Software\Microsoft\Office\12.0\Outlook\PST
• Outlook 2010
  HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Outlook\PST
• Outlook 2013
  HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Outlook\PST

Here you must create and set 2 new DWORD values (note that these values are case sensitive);

• WarnLargeFileSize
  Don’t set this higher than 4090445042 (decimal) or f3cf3cf2 (hexadecimal)
• MaxLargeFileSize
  Don’t set this higher than 4294967295 (decimal) or ffffffff (hexadecimal)

The first value is how many MB a user can write to a pst-file. The second value is how many MB the system can write to a pst-file. This difference has to be at least 5% since there is more written to a pst-file than just user data.

Above the maximum size of a pst-file has been set to 100GB with a warning at 95GB.

Via Group Policies

Not comfortable editing the Registry? You can then use Group Policies as well even when you are on a home computer. For instructions on how to use Group Policies see this guide.
The settings for adjusting the pst filesize can be found in the section Miscellaneous-> PST Settings. The following 2 settings need to be modified;

• Large PST: Absolute maximum size
  Don’t set this higher than 4294967295
• Large PST: Size to disable adding new content
  Don’t set this higher than 4090445042

Windows 7 Offline files will not go Online when connected to network

Issue
Several laptop users move between networks, domain, home, etc and when they attempt to access DFS shares explorer status is working offline.  The issue only resolves it self after a reboot. Connecting directly to the share works and i am able to ping network resources.  This behavior occurs for VPN users as well.

Possible Causes

"slow-link mode". In win7 (with default settings) a client will enter slow-link mode if the latency to the server is above 80ms. In slow-link mode all writes are made to the local cache and a background sync only happens every 6 hours.  Depending on your connection the default slow link detection speed is 64,000 bps

On client computers running Windows 7 or Windows Server 2008 R2, a shared folder automatically transitions to the slow-link mode if the round-trip latency of the network is greater than 80 milliseconds, or as configured by the "Configure slow-link mode" policy. After transitioning a folder to the slow-link mode, Offline Files synchronizes the user's files in the background at regular intervals, or as configured by the 'Configure Background Sync' policy. While in slow-link mode, Windows periodically checks the connection to the folder and brings the folder back online if network speeds improve.

If you do not configure the "Configure slow-link mode" policy setting, computers running Windows Vista or Windows Server 2008 will not transition a shared folder to the slow-link mode. Computers running Windows 7 or Windows Server 2008 R2 will use the default latency value of 80 milliseconds when transitioning a folder to the slow-link mode. To prevent computers running Windows 7 or Windows Server 2008 R2 from using the slow-link mode, disable this policy.

Option 1 Disable it in the Group policy to see if it helps (feedback welcome),
Check the following two policy settings that control the offline file slow-link mode and speed:
Path: Computer Policy\Administrative Templates\Network\Offline Files
Policies:

*Configure slow-link mode

*Configure slow-link speed

Option 2 Configure Forced silent auto reconnection

1. Click Start, type REGEDIT in search bar, and then click OK.

2. Locate and click the following registry subkey:
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\NetCache

3. Click Edit, point to New, and then click DWORD Value.

4. Type SilentForcedAutoReconnect, and then press ENTER to name the value.

5. Double-click SilentForcedAutoReconnect.

6. In the Value data box, type 1, and then click OK.

Option3 Computer Policy\Administrative Templates\Network\Offline Files\Action on server disconnect

Tip: To configure this setting without establishing a setting, in Windows Explorer, on the Tools menu, click Folder Options, click the Offline Files tab, click Advanced, and then select an option in the "When a network connection is lost" section.

Also, see the "Non-default server disconnect actions" setting.