0

Under account settings Outlook2016.
One has the option mail to keep offline in the gui, to cache Email.

Problem: For unknown reasons it stays at 1 month or all time.
One should be able to alter the period by policy or registry:

HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\xx.0\Outlook\Cached Mode  
 xx.0 =   
  Outlook 2016 is 16.0  
  Outlook 2013 is 15.0  
  Outlook 2010 is 14.0  
  Outlook 2007 is 12.0  
  Outlook 2003 is 11.0  
  
Create a DWORD value of SyncWindowSetting, and then set the desired value:  
0 = All (whole mailbox)  
1 = 1 month of email items  
3 = 3 months of email items  
6 = 6 months of email items  
12 = 1 year of email items  
24 = 2 years of email items  
36 = 3 years of email items (Outlook 2016 only)  
60 = 5 years of email items (Outlook 2016 only)

I even added the Dword value Enable and set it to 1.

I need to have syncWindowSetting to 12, to keep one year of email cached in the OST, however outlook seams to completely ignore these values, and sticks to one month only or all
Any ideas to get it working for only 1 year are welcome

a registry export of my outlook settings is below:

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\16.0\Outlook\Cached Mode]
"SyncWindowSetting"=dword:0000000c
"SyncWindowSettingDays"=dword:00000000
"Enable"=dword:00000001

However whatever i do inside outlook 2016 it stays at 1 month.
As for registry permissions, the user and system can read above entries.
how it looks in outlook 2016

Peter
  • 115
  • 1
  • 8

1 Answers1

1

Except SyncWindowSetting, another DWORD key is also required to be added in registry:

DWORD: SyncWindowSetting Value: 12

DWORD: SyncWindowSettingDays Value: 0

The following table records the corresponding values of the two keys(Update allows administrators to set additional default mail and calendar synchronization windows for new Exchange accounts in Outlook 2016):

enter image description here

My test result is for your reference: enter image description here

enter image description here

Edit: Based on my research, for Cached Exchange mode, we could use the above keys to modify the default sync days of emails, but there're no registry keys to modify the sync days of an ActiveSync account. The following link about registry keys which are used for modifying sync days is for your reference: Cached Exchange Mode Sync Settings & Exchange ActiveSync

Ivan_Wang
  • 1,333
  • 1
  • 4
  • 4
  • Yes I got them both but it's still not working – Peter Jan 20 '21 at 21:05
  • Did you restart Outlook after modifying the registry keys? Could you please attach the registry settings in your edited post?(I typed a wrong name of the key "Cached Mode" before, so that the "Mail to keep offline" didn't apply the change.) I will compare them with mine and see if there is any difference. – Ivan_Wang Jan 21 '21 at 01:45
  • I show the registry in my question now, as i couldnt use such text formatting in herre. – Peter Jan 21 '21 at 07:48
  • The two registry keys are only used to modify the default setting "Mail to keep offline" with a specific value, if you configure a new mailbox in Outlook, the settings will apply to the new account(You could navigate to Account Settings, then you will find "Mail to keep offline" is the specific value.), however, the two keys won't modify the default setting if you configure mailboxes with the way "outlook.com or exchange activesync compatible service". – Ivan_Wang Jan 22 '21 at 09:12
  • It doesnt apply to activesync users ?? We use outlook with activesync (against kopano mail server) – Peter Jan 22 '21 at 10:44
  • Based on my research, for Cached Exchange mode, we could use the above keys to modify the default sync days of emails, but there're no registry keys to modify the sync days of an ActiveSync account. The following link about registry keys which are used for modifying sync days is for your reference: Cached Exchange Mode Sync Settings(https://admx.help/?Category=Office2016&Policy=outlk16.Office.Microsoft.Policies.Windows::L_CachedExchangeModeSyncSlider) & Exchange ActiveSync(https://admx.help/?Category=Office2016&Policy=outlk16.Office.Microsoft.Policies.Windows::L_EASSyncFrequency) – Ivan_Wang Jan 25 '21 at 08:35
  • Ok Ivan maybe update it in your asnwer, so that others having the same issue as me will look no futher, i didnt knew that. – Peter Jan 25 '21 at 09:45
  • @user3800527 Thanks for your suggestion, I have updated this point in my answer. If it's helpful to you, you could mark the best answer; If you have any similar issue after that, you're welcome to post. Have a nice day:-) – Ivan_Wang Jan 26 '21 at 01:35
  • I tried Ivan_Wang's guide on my 365 account in Outlook, but it didn't work. It's not changing the slider. There **must** be a reg setting somewhere for that slider. – user242114 Jul 24 '23 at 20:35