Hello 

We are experiencing serious issues after installing smarter mail 16.x and upgrade to latest.  Following are the teething issues we have faced so far

1. Smarter mail service: Mailservice.exe is abruptly stopped, we need to restart service then.

2. After installation of Latest upgrade, domain configuration files corrupted. Unable to login from a domain administrator account We created a new user as a domain administrator to get the access of domain. 

3. No user has seen after login to the domain , Though user's mailboxes are there in the drive. we have to create all the users from scratch and attached the folder, rebuild and reindex to get the login and access to the mails for each user. 

4. Search is not still working for any users 

5. some of the domains are failed to load. Setting.json file got corrupted, we have restored the backup

6. even in one domain after restoring the setting.json the domain was unable to load, finally, we have to recreate the entire domain and their users from scratch. This happens after restarting of mail server.

7 some of the user data is also corrupted. The date indexing is showing incorrect. 

In our windows event logs following for mailservice.exe

Faulting application name: MailService.exe, version: 100.0.7153.19227, time stamp: 0x5d4475ad
Faulting module name: KERNELBASE.dll, version: 10.0.17763.292, time stamp: 0xb51bba8e
Exception code: 0xe0434352
Fault offset: 0x0000000000055549
Faulting process id: 0x1904
Faulting application start time: 0x01d54d03e03d4f06
Faulting application path: C:\Program Files (x86)\SmarterTools\SmarterMail\Service\MailService.exe
Faulting module path: C:\Windows\System32\KERNELBASE.dll
Report Id: ccd188fb-26b3-42c7-82ee-1b44e374ff02
Faulting package full name:
Faulting package-relative application ID:

Application: MailService.exe
Framework Version: v4.0.30319
Description: The process was terminated due to an unhandled exception.
Exception Info: System.IndexOutOfRangeException
   at Lucene.Net.Util.IOUtils.ReThrow(System.Exception)
   at Lucene.Net.Index.IndexWriter.HandleMergeException(System.Exception, OneMerge)
   at Lucene.Net.Index.IndexWriter.Merge(OneMerge)
   at Lucene.Net.Index.ConcurrentMergeScheduler.DoMerge(OneMerge)
   at Lucene.Net.Index.ConcurrentMergeScheduler+MergeThread.Run()

Exception Info: Lucene.Net.Index.MergePolicy+MergeException
   at Lucene.Net.Index.ConcurrentMergeScheduler.HandleMergeException(System.Exception)
   at Lucene.Net.Index.ConcurrentMergeScheduler+MergeThread.Run()
   at System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean)
   at System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean)
   at System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object)
   at System.Threading.ThreadHelper.ThreadStart()

Lucene.Net.Index.MergePolicy+MergeException: System.IndexOutOfRangeException: Index was outside the bounds of the array.
   at Lucene.Net.Util.IOUtils.ReThrow(Exception th)
   at Lucene.Net.Index.IndexWriter.HandleMergeException(Exception t, OneMerge merge)
   at Lucene.Net.Index.IndexWriter.Merge(OneMerge merge)
   at Lucene.Net.Index.ConcurrentMergeScheduler.DoMerge(OneMerge merge)
   at Lucene.Net.Index.ConcurrentMergeScheduler.MergeThread.Run() ---> System.IndexOutOfRangeException: Index was outside the bounds of the array.
   at Lucene.Net.Util.IOUtils.ReThrow(Exception th)
   at Lucene.Net.Index.IndexWriter.HandleMergeException(Exception t, OneMerge merge)
   at Lucene.Net.Index.IndexWriter.Merge(OneMerge merge)
   at Lucene.Net.Index.ConcurrentMergeScheduler.DoMerge(OneMerge merge)
   at Lucene.Net.Index.ConcurrentMergeScheduler.MergeThread.Run()
   --- End of inner exception stack trace ---
   at Lucene.Net.Index.ConcurrentMergeScheduler.HandleMergeException(Exception exc)
   at Lucene.Net.Index.ConcurrentMergeScheduler.MergeThread.Run()
   at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Threading.ThreadHelper.ThreadStart()

Please help us to resolve ASAP