From last two days I can see following in SQL Server errorlog.

```
AppDomain 2 (mssqlsystemresource.dbo[runtime].1) unloaded.
&
AppDomain 2 (mssqlsystemresource.dbo[runtime].1) is marked for unload due to memory pressure.

```

I have system environment like this :

```
OS- microosft windows server 2012 R2 Standard
processors - Intel(R) Xeon(R) CPU E5-2670 0 @2.60 GHz
Installed Memory (RAM) - 8GB
Hardware Information - VMWare, Inc. VMware Virtual Platform
SQL Server - Microsoft SQL Server Enterprise (64-bit)

```

I have checked out in local server for yesterday's event log . I have found thses events 

```
Server Name ID  Severity    Source            Log      Date and Time
ABC    1008 Error   Microsoft-Windows-Perflib Application 10/01/2015 2:21
ABC     2   Error   TeamCentral      Application      9/30/2015 4:20:41 PM
ABC    1309 Warning ASP.NET 4.0.30319.0 Application 9/30/2015 4:20:41 PM
ABC   10016 Error Microsoft-Windows-DistributedCOM System 9/30/2015 4:06:23 PM
ABC   10016 Error   Microsoft-Windows-DistributedCOM    System  9/30/2015 4:00:04 PM
ABC 10016   Error   Microsoft-Windows-DistributedCOM    System  9/30/2015 4:00:02 PM
ABC 2   Error   TeamCentral Application 9/30/2015 3:55:13 PM
ABC 1309    Warning ASP.NET 4.0.30319.0 Application 9/30/2015 3:55:13 PM
ABC 10016   Error   Microsoft-Windows-DistributedCOM    System  9/30/2015 3:40:06 PM
ABC 10016   Error   Microsoft-Windows-DistributedCOM    System  9/30/2015 3:40:03 PM
ABC 1309    Warning ASP.NET 4.0.30319.0 Application 9/30/2015 3:23:54 PM
ABC 2   Error   TeamCentral Application 9/30/2015 3:23:54 PM
ABC 2   Error   TeamCentral Application 9/30/2015 3:22:48 PM
ABC 1309    Warning ASP.NET 4.0.30319.0 Application 9/30/2015 3:22:48 PM
ABC 2   Error   TeamCentral Application 9/30/2015 3:21:43 PM
ABC 1309    Warning ASP.NET 4.0.30319.0 Application 9/30/2015 3:21:43 PM
ABC 2   Error   TeamCentral Application 9/30/2015 3:18:24 PM
ABC 1309    Warning ASP.NET 4.0.30319.0 Application 9/30/2015 3:18:24 PM
ABC 2   Error   TeamCentral Application 9/30/2015 3:16:49 PM
ABC 1309    Warning ASP.NET 4.0.30319.0 Application 9/30/2015 3:16:49 PM
ABC 1309    Warning ASP.NET 4.0.30319.0 Application 9/30/2015 3:15:43 PM
ABC 2   Error   TeamCentral Application 9/30/2015 3:15:43 PM
ABC 1010    Error   Microsoft-Windows-Perflib   Application 9/30/2015 10:42:00 AM

```

And in Event I am getting such type of message :

```
    Event code: 3005 
Event message: An unhandled exception has occurred. 
Event time: 9/30/2015 4:20:41 PM 
Event time (UTC): 9/30/2015 1:20:41 PM 
Event ID: 72c24cb89beb4d7f80bec250aaa686e3 
Event sequence: 757 
Event occurrence: 17 
Event detail code: 0 

Application information: 
    Application domain: /XX/XXXX/1/ROOT/TeamCentral-2-130850431401577570 
    Trust level: Full 
    Application Virtual Path: /TeamCentral 
    Application Path: C:\XXXX\wwwroot\TeamCentral\ 
    Machine name: ABC

Process information: 
    Process ID: 2180 
    Process name: w3wp.exe 
    Account name: NT AUTHORITY\NETWORK SERVICE 

Exception information: 
    Exception type: HttpException 
    Exception message: The remote host closed the connection. The error code is 0x800704CD.
   at System.Web.Hosting.IIS7WorkerRequest.RaiseCommunicationError(Int32 result, Boolean throwOnDisconnect)
   at System.Web.Hosting.IIS7WorkerRequest.ExplicitFlush()
   at System.Web.HttpResponse.Flush(Boolean finalFlush, Boolean async)
   at System.Web.HttpWriter.WriteFromStream(Byte[] data, Int32 offset, Int32 size)
   at DevExpress.Web.ASPxClasses.Internal.HttpUtils.WriteFileToResponse(Page page, MemoryStream stream, String fileName, Boolean saveAsFile, String fileFormat, String contentType)
   at DevExpress.Web.ASPxClasses.Internal.HttpUtils.WriteFileToResponse(Page page, MemoryStream stream, String fileName, Boolean saveAsFile, String fileFormat)
   at DevExpress.Web.ASPxGridView.Export.ASPxGridViewExporter.WriteToResponse(String fileName, Boolean saveAsFile, String fileFormat, ExportToStream getStream, ExportOptionsBase options)
   at DevExpress.Web.ASPxGridView.Export.ASPxGridViewExporter.WriteXlsxToResponse(String fileName, Boolean saveAsFile)
   at DevExpress.Web.ASPxGridView.Export.ASPxGridViewExporter.WriteXlsxToResponse(String fileName)
   at InfoArch.Web.Grid.ExportHelper.Response(ExportFileType fileType, Grid structure)
   at InfoArch.Web.Grid.GridManager.SaveToXlsx(String filename)
   at System.Web.UI.WebControls.ImageButton.OnClick(ImageClickEventArgs e)
   at System.Web.UI.WebControls.ImageButton.RaisePostBackEvent(String eventArgument)
   at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)

Request information: 
    Request URL: http://ABC/TeamCentral/Reporting/GridView.aspx?layoutid=38&mf=report&where=&description=PZF6Q0PKJzWQDHkN08mydZNuJ3fZ(:#cd6TgCAL0hv4u4=&screenheight=618 
    Request path: /TeamCentral/Reporting/GridView.aspx 
    User host address:XXX.XXX.XX.XXX 
    User: rafeek 
    Is authenticated: True 
    Authentication Type:  
    Thread account name: NT AUTHORITY\NETWORK SERVICE 

Thread information: 
    Thread ID: 190 
    Thread account name: NT AUTHORITY\NETWORK SERVICE 
    Is impersonating: False 
    Stack trace:    at System.Web.Hosting.IIS7WorkerRequest.RaiseCommunicationError(Int32 result, Boolean throwOnDisconnect)
   at System.Web.Hosting.IIS7WorkerRequest.ExplicitFlush()
   at System.Web.HttpResponse.Flush(Boolean finalFlush, Boolean async)
   at System.Web.HttpWriter.WriteFromStream(Byte[] data, Int32 offset, Int32 size)
   at DevExpress.Web.ASPxClasses.Internal.HttpUtils.WriteFileToResponse(Page page, MemoryStream stream, String fileName, Boolean saveAsFile, String fileFormat, String contentType)
   at DevExpress.Web.ASPxClasses.Internal.HttpUtils.WriteFileToResponse(Page page, MemoryStream stream, String fileName, Boolean saveAsFile, String fileFormat)
   at DevExpress.Web.ASPxGridView.Export.ASPxGridViewExporter.WriteToResponse(String fileName, Boolean saveAsFile, String fileFormat, ExportToStream getStream, ExportOptionsBase options)
   at DevExpress.Web.ASPxGridView.Export.ASPxGridViewExporter.WriteXlsxToResponse(String fileName, Boolean saveAsFile)
   at DevExpress.Web.ASPxGridView.Export.ASPxGridViewExporter.WriteXlsxToResponse(String fileName)
   at InfoArch.Web.Grid.ExportHelper.Response(ExportFileType fileType, Grid structure)
   at InfoArch.Web.Grid.GridManager.SaveToXlsx(String filename)
   at System.Web.UI.WebControls.ImageButton.OnClick(ImageClickEventArgs e)
   at System.Web.UI.WebControls.ImageButton.RaisePostBackEvent(String eventArgument)
   at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)

Custom event details: 

```

I have gone through the Stackexchange before asking the question i have found out the ref [App domain is marked for unload due to memory pressure](https://dba.stackexchange.com/questions/63720/app-domain-is-marked-for-unload-due-to-memory-pressure) but some point of view , unable to understand the event log message.

Output of `select @@version`;

> 
> Microsoft SQL Server 2012 (SP1) - 11.0.3000.0 (X64) Oct 19 2012
>  13:38:57 Copyright (c) Microsoft Corporation Enterprise Edition
>  (64-bit) on Windows NT 6.2 (Build 9200: ) (Hypervisor)
> 
> 
> 

and output of `exec sp_configure`;

```
Name                    minimum     maximum      config_value     run_value 
max server memory (MB)   128        2147483647    2147483647     2147483647

```

Any suggestion would be appreciated.