Outlook crashing when sending

Using Exchange 2013 and Outlook 2016

Recently i have found that all of my users are having this issue.  the OAB wont update and also Outlook crashes occasionally when sending emails.  emails send normally most of the time but sometimes it crashes and you have to retype the email.  by crash i mean goes white and you get the not responding message and you have to exit as it never come back.  

I am finding that outlook is creating a .tmp filin the appdata>local>Microsoft>Outlook folder every time you open outlook.  the exisiting OAB does not update at all and if you remove the OAB and try to download again it does not create a new one.  outlook itself shows 'Updating Address Book' in the status bar and this never goes away.  if you try to use the client to update the address book it either fails or crashes.

other than this outlook works fine.  i have over 50 PC's all having the same issue.  All runnign office 2016 and windows 10.  updates have been appllied to all of them and are running latest office and windows.  i have tried all this using general user and domain admin and get the same result so im pretty sure its not permissions.  i have used exchange PS to run Get-AddressList | update-AddressList and Get-OfflineAddressBook | Update-OfflineAddressBook  these comeplete but its made no difference.

the only thing i can see in the event log as an ESENT error for cortana:
Log Name:      Application
Source:        ESENT
Date:          17/01/2019 10:09:18
Event ID:      413
Task Category: Logging/Recovery
Level:         Error
Keywords:      Classic
User:          N/A
Computer:      143DELL.Packhouse.Winterwood.co.uk
Description:
DllHost (9504,R,98) Microsoft.Windows.Cortana_cw5n1h2txyewy_NOEDP_LEGACY_IDB: Unable to create a new logfile because the database cannot write to the log drive. The drive may be read-only, out of disk space, misconfigured, or corrupted. Error -1032.
Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
  <System>
    <Provider Name="ESENT" />
    <EventID Qualifiers="0">413</EventID>
    <Level>2</Level>
    <Task>3</Task>
    <Keywords>0x80000000000000</Keywords>
    <TimeCreated SystemTime="2019-01-17T10:09:18.392082000Z" />
    <EventRecordID>146588</EventRecordID>
    <Channel>Application</Channel>
    <Computer>143DELL.Packhouse.Winterwood.co.uk</Computer>
    <Security />
  </System>
  <EventData>
    <Data>DllHost</Data>
    <Data>9504,R,98</Data>
    <Data>Microsoft.Windows.Cortana_cw5n1h2txyewy_NOEDP_LEGACY_IDB: </Data>
    <Data>-1032</Data>
  </EventData>
</Event>

and

Log Name:      Application
Source:        ESENT
Date:          17/01/2019 10:09:18
Event ID:      486
Task Category: General
Level:         Error
Keywords:      Classic
User:          N/A
Computer:      143DELL.Packhouse.Winterwood.co.uk
Description:
DllHost (9504,R,98) Microsoft.Windows.Cortana_cw5n1h2txyewy_NOEDP_LEGACY_IDB: An attempt to move the file "C:\Users\martin.PACKHOUSE\AppData\Local\Packages\Microsoft.Windows.Cortana_cw5n1h2txyewy\AppData\Indexed DB\edb.log" to "C:\Users\martin.PACKHOUSE\AppData\Local\Packages\Microsoft.Windows.Cortana_cw5n1h2txyewy\AppData\Indexed DB\edb0000C.log" failed with system error 183 (0x000000b7): "Cannot create a file when that file already exists. ".  The move file operation will fail with error -1814 (0xfffff8ea).
Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
  <System>
    <Provider Name="ESENT" />
    <EventID Qualifiers="0">486</EventID>
    <Level>2</Level>
    <Task>1</Task>
    <Keywords>0x80000000000000</Keywords>
    <TimeCreated SystemTime="2019-01-17T10:09:18.390084100Z" />
    <EventRecordID>146587</EventRecordID>
    <Channel>Application</Channel>
    <Computer>143DELL.Packhouse.Winterwood.co.uk</Computer>
    <Security />
  </System>
  <EventData>
    <Data>DllHost</Data>
    <Data>9504,R,98</Data>
    <Data>Microsoft.Windows.Cortana_cw5n1h2txyewy_NOEDP_LEGACY_IDB: </Data>
    <Data>C:\Users\martin.PACKHOUSE\AppData\Local\Packages\Microsoft.Windows.Cortana_cw5n1h2txyewy\AppData\Indexed DB\edb.log</Data>
    <Data>C:\Users\martin.PACKHOUSE\AppData\Local\Packages\Microsoft.Windows.Cortana_cw5n1h2txyewy\AppData\Indexed DB\edb0000C.log</Data>
    <Data>-1814 (0xfffff8ea)</Data>
    <Data>183 (0x000000b7)</Data>
    <Data>Cannot create a file when that file already exists. </Data>
  </EventData>
</Event>

these 2 appear over and over again.  i have tried reindexing in outlook still no change.  this is also occurring on brand new installs fresh out of the box.  i have also tried repair office and remove it all together and reinstall and its always the same

sorry about all the info but i have been working on this for some time and have not made any progress so any advice or answer would be very useful

thanks

Martin