Diagnose MissingWebPart and MissingAssembly issues from the SharePoint Health Analyzer using PowerShell

In this article I am going to focus on MissingWebPart and MissingAssembly errors. As stated in previous articles, there is no silver bullet to solving these errors in all cases, but the scripts offered here will allow you troubleshoot the errors further to find exactly where they are happening in the content database. Once you know this, you have a fighting chance of being able to solve the problem.
MissingWebPart Error
In this example, I have received the following error whilst running a Test-SPContentDatabase operation after a content database migration from SharePoint 2007 to 2010. It also appears in the SharePoint Health Analyzer under the “Configuration” category with the title “Missing server side dependencies”:
Category        : MissingWebPart
Error           : True
UpgradeBlocking : False
Message         : WebPart class [4575ceaf-0d5e-4174-a3a1-1a623faa919a] is referenced [2] times in the database [SP2010_Content], but is not installed on the current farm. Please install any feature/solution which contains this web part.
Remedy          : One or more web parts are referenced in the database [SP2010_Content], but are not installed on the current farm. Please install any feature or solution which contains these web  parts.
As you can see, the error gives you a “WebPart class” GUID, the name of the content database, and how many times it is referenced in the database, but little else. What we need to find out here is either the name of the web part or on which pages it is referenced in the database.
For this I am going to reuse the Run-SQLQuery PowerShell script that I introduced in my article on MissingSetupFile errors:

function Run-SQLQuery ($SqlServer, $SqlDatabase, $SqlQuery)
{
$SqlConnection = New-Object System.Data.SqlClient.SqlConnection
$SqlConnection.ConnectionString = "Server =" + $SqlServer + "; Database =" + $SqlDatabase + "; Integrated Security = True"
$SqlCmd = New-Object System.Data.SqlClient.SqlCommand
$SqlCmd.CommandText = $SqlQuery
$SqlCmd.Connection = $SqlConnection
$SqlAdapter = New-Object System.Data.SqlClient.SqlDataAdapter
$SqlAdapter.SelectCommand = $SqlCmd
$DataSet = New-Object System.Data.DataSet
$SqlAdapter.Fill($DataSet)
$SqlConnection.Close()
$DataSet.Tables[0]
}

Once you have loaded the function in a PowerShell console, you can run it by using the Run-SQLQuery command with the options relevant to your deployment. For [MissingWebPart] errors, you need to run a SQL SELECT query on the “AllDocs” table in the content database exhibiting the problem, joining to the “AllWebParts” table in order to find details about the missing web part. For example, you would type the following command to find details of the web part with the class ID “4575ceaf-0d5e-4174-a3a1-1a623faa919a”, as reported in the error above:

Run-SQLQuery -SqlServer "SQLSERVER" -SqlDatabase "SP2010_Content" -SqlQuery "SELECT * from AllDocs inner join AllWebParts on AllDocs.Id = AllWebParts.tp_PageUrlID where AllWebParts.tp_WebPartTypeID = '4575ceaf-0d5e-4174-a3a1-1a623faa919a'" | select Id, SiteId, DirName, LeafName, WebId, ListId, tp_ZoneID, tp_DisplayName | Format-List

Yes, it is a pretty long command, but it will produce a very useful output, as shown in this example:
Id             : 6ab5e70b-60d8-4ddf-93cb-6a93fbc410be
SiteId         : 337c5721-5050-46ce-b112-083ac52f7f26
DirName        : News/Pages
LeafName       : ArticleList.aspx
WebId          : dcc93f3e-437a-4fae-acea-bb15d5c4ea7d
ListId         : 7e13fe6c-3670-4d46-9601-832e3eb6a1e4
tp_ZoneID      : Body
tp_DisplayName :
Id             : b3fcfcd2-2f02-4fe9-93e4-9c9b5ecddf5b
SiteId         : 337c5721-5050-46ce-b112-083ac52f7f26
DirName        : Pages
LeafName       : Welcome.aspx
WebId          : 2ae0de59-a008-4244-aa66-d8f76c79f1ad
ListId         : d8f083f0-16b9-43d0-9aaf-4e9fffecd6cc
tp_ZoneID      : RightColumnZone
tp_DisplayName :
This tells us that the web part has been found on two pages (the references mentioned in the MissingWebPart error). SiteId tells us the site collection and WebId the site where the pages are located. We also have a DirName showing the relative path and the page name itself against the LeafName property. If you’re lucky, you might get the display name of the web part against the tp_DisplayName property, but if not, you should at least be able to tell which zone the web part has been added to by looking at the tp_ZoneID property.
Easily the best way of resolving these issues is to do as the error suggests and install the missing feature or solution containing the web part, but if this is not possible or feasible to do in your scenario, we can discover the site collection URL from the GUIDs using PowerShell and then remove the offending web parts from the pages specified.
To find the site collection URL using the information output from the query, type the following command:

$site = Get-SPSite -Limit all | where {$_.Id -eq "337c5721-5050-46ce-b112-083ac52f7f26"}
$site.Url

One you have the site collection URL, you can use the relative path specified by the DirName property to find the location of the file. To remove the web part from the page, type the page URL in the browser and add ?contents=1 to the end of it. For example, to open the web part maintenance page for the ArticleList.aspx page specified in the output, type the following URL in the browser:

http://portal/news/pages/articlelist.aspx?contents=1

You can then highlight the offending web part (normally called ErrorWebPart for MissingWebPart errors) by ticking the box and clicking Delete. The screenshot below shows a web part maintenance page to give you an idea of the UI, but not an example of an ErrorWebPart as I had already removed them!

Note: If you remove an ErrorWebPart from a publishing page with versioning switched on, you may have to delete all earlier versions of the page before the error disappears from the SharePoint Health Analyzer or Test-SPContentDatabase report. This is because the web part will still be referenced from these versions, even though you removed it from the currently published page.
MissingAssembly Error
MissingAssembly errors look similar to this one:
Category        : MissingAssembly
Error           : True
UpgradeBlocking : False
Message         : Assembly [PAC.SharePoint.Tagging, Version=1.0.0.0, Culture=neutral, PublicKeyToken=b504d4b6c1e1a6e5] is referenced in the database [SP2010_Content], but is not installed on the current farm. Please install any feature/solution which contains this assembly.
Remedy          : One or more assemblies are referenced in the database [SP2010_Content], but are not installed on the current farm. Please install any feature or solution which contains these assemblies.
I normally find MissingAssembly errors appear as the result of an event receiver, which is still registered on a list or library but part of a feature/solution no longer present on the farm.
In most cases, you may be able to look at the assembly name reported in this error and know what the problem is straight away. As before, the best way of resolving this is to reinstall the missing solution file. However, if you are not able to install the solution (e.g., maybe it only works in SharePoint 2007 and not 2010), then you may want to find the lists where the event receiver is installed and either remove the event receiver from the lists or delete the lists themselves.
To troubleshoot this issue we can re-use the Run-SQLQuery function used to help find missing web parts above. The table we need to look at this time though is called “EventReceivers”. For example, you would type the following command to find details of the assembly called “PAC.SharePoint.Tagging, Version=1.0.0.0, Culture=neutral, PublicKeyToken=b504d4b6c1e1a6e5”, as reported in the error above:

Run-SQLQuery -SqlServer "SQLSERVER" -SqlDatabase "SP2010_Content" -SqlQuery "SELECT * from EventReceivers where Assembly = ‘PAC.SharePoint.Tagging, Version=1.0.0.0, Culture=neutral, PublicKeyToken=b504d4b6c1e1a6e5'" | select Id, Name, SiteId, WebId, HostId, HostType | Format-List

This will produce an output similar to the following:
Id       : 657a472f-e51d-428c-ab98-502358d87612
Name     :
SiteId   : 337c5721-5050-46ce-b112-083ac52f7f26
WebId    : 2ae0de59-a008-4244-aa66-d8f76c79f1ad
HostId   : 09308020-45a8-41e4-bbc0-7c8d8cd54132
HostType : 2
Id       : 0f660612-6be0-401e-aa1d-0ede7a9af8da
Name     :
SiteId   : 337c5721-5050-46ce-b112-083ac52f7f26
WebId    : 2ae0de59-a008-4244-aa66-d8f76c79f1ad
HostId   : 09308020-45a8-41e4-bbc0-7c8d8cd54132
HostType : 2
As with the MissingWebPart error before, we can use these GUIDs to get the site collection and site hosting the list with the missing event receiver, as follows:

$site = Get-SPSite -Limit all | where {$_.Id -eq "337c5721-5050-46ce-b112-083ac52f7f26"}
$web = $site | Get-SPWeb -Limit all | where {$_.Id -eq "2ae0de59-a008-4244-aa66-d8f76c79f1ad"}
$web.Url

The HostId property is the GUID of the object containing the event receiver. The HostType is the object type – in this case, HostType “2” means the event receiver host is a list. You can look at the other host types by checking this article on MSDN: http://msdn.microsoft.com/en-us/library/ee394866(v=prot.13).aspx.
Now we know the GUID refers to a list, we can get it using PowerShell with this command:

$list = $web.Lists | where {$_.Id -eq "09308020-45a8-41e4-bbc0-7c8d8cd54132"}

To remove the list completely, type the following command:

$list.Delete()

To keep the list intact and just remove the offending event receiver, copy the Id property from the Run-SQLQuery output into this command:

$er = $list.EventReceivers | where {$_.Id -eq "657a472f-e51d-428c-ab98-502358d87612"}
$er.Delete()

If you do decide to delete the list completely, ensure you also remove it from the site Recycle Bin and Site Collection Recycle Bin to ensure the file is removed from the content database. If not, the error may not disappear from the Health Analyzer or Test-SPContentDatabase operation.

http://get-spscripts.com/2011/08/diagnose-missingwebpart-and.html