Resolving Missing References when upgrading to SharePoint 2010

When doing some migrations from SP 2007 to SP 2010 there are some issue we commonly find in Test-SPContentDatabase command.

Please find the some of the common issues we see in report and the workaround for the issues and also solutions for the same.

Missing Site definition:
Log entry : Sites in database {} has reference(s) to a missing site definition, Id = {}, Lcid = {}. Remedy: The site definitions with Id {} is referenced in the database {}, but is not installed on the current farm. The missing site definition may cause upgrade to fail. Please install any solution which contains the site definition and restart upgrade if necessary
SQL query to fetch the details :
select fullurl from webs where webtemplate = {Template id from the above error message}
Resolution : Try to open the sites url got from the above query and see if site works as expected if not delete site and perform the migration.

Missing Features : 
Log entry : Database {} has reference(s) to a missing feature: Id = {}. Remedy: The feature with Id {} is referenced in the database  {}, but is not installed on the current farm. The missing feature may cause upgrade to fail. Please install any solution which contains the feature and restart upgrade if necessary.
SQL query to fetch the details :
select fullurl, description from features join webs on (features.webid = webs.id) where featureid = { Feature ID }
Resolution : Open the Url and see all the feature related files were placed in the new envrionment if not place all the feature related files on all the WFE servers. If still problem persists deactivate the feature and perform the migration. Then insall the same feature in new environment separately.

Missing Setup File

Log Entry:
File {} is referenced [1] times in the database {}, but is not installed on the current farm. Please install any feature/solution which contains this file. Remedy: One or more setup files are referenced in the database {}, but are not installed on the current farm. Please install any feature or solution which contains these files.
SQL Query : 
select * from AllDocs where SetupPath like '%{ Path got from above error message}%'

Resolution : Mostly this issue will occur only when you try to perform a migration on a site collection / sub site which is not accessibly or corrupted sites. Please fix the issues in current site / sub site or delete the issue causing sites and perform migration.

Missing Web Part

Log Entry:
WebPart class {} is referenced [1] times in the database {}, 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 {}, but are not installed on the current farm. Please install any feature or solution which contains these webparts.
SQL Query : 
select s.fullurl, d.DirName, d.leafname, tp_ZoneID, tp_partOrder
from webparts p
join alldocs d on (p.tp_PageUrlID = d.ID)
join sites s on (s.id = p.tp_siteid) 
where tp_WebPartTypeId  = ‘{ WebPart ID from aove error message }’
Resolution : 
You can get the site that has the web part. You will usually see that the web part does not render properly or says something about an error for a particular web part. That is usually the issue. it can be a bit tricky if everything looks ok though. In other words you may not see the issue on the site though. The problem in this case is usually that someone has closed a web part instead of deleting it.
There are two ways to delete the web parts.

1. Add a ?contents=1 to bring up the Web Part Maintenance page. Click the ones that says Error and then click the Delete button. Much simpler
2. To delete it you need to add it back to the page and then delete it. To add them click the Add a web part button on one of the zones and then click the Advanced Web Part gallery and options link at the bottom right on the screen. Then in the Add Web Parts panel that shows up on the page, click the Closed Web Parts collection. The web parts that have errors will say (Web Part Error) in the list of web parts before you add them.

NOTE: The query also has the zone id which tells you what zone it is in. This is usually something life left, right, top, bottom, etc. You can use this to get an idea of where on the page the web part is. The problem is that if it was closed it appears to show the last zone it was part of instead of null or something like that. Each zone can have multiple web parts. The order that they are displayed is shown in the partOrder. 1 = first, 2 = second, etc.

Missing Assembly

Log Entry:
Assembly {} is referenced in the database {}, 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 {}, but are not installed on the current farm. Please install any feature or solution which contains these assemblies.
SQL Query : 
SELECT s.fullurl, webs.fullurl, assembly, hostType
from EventReceivers e
join webs on (e.webid = webs.id)
join sites s on (s.id = e.siteid)
where Assembly = ‘{ webpart 4 part details from the above errror message}'

Comments: 
I went to the url (that I got from the query above) and investigated. I didn’t find that very useful. Then I looked at the hostType column in the results and in my case had a value of 2. Which according to the Microsoft reference is for a list. So, I used SharePoint Manager to go to each of the lists for the site and looked at the EventReceivers Property (Collection). You can then delete the appropriate Event Receiver using Powershell. Do the deletion at your own risk. I tried it on a copy of the content database and I didn’t see any adverse effects, and I have read that others have done it also, but it seems a bit risky to me in general. Try this on a copy of your content database before you do it on production would be my recommendation. You can also use SharePoint Manager to delete any hidden lists which have the EventReceiver. Again, use caution. If this is not a show stopper, you may consider just leaving the issue alone. That is what I did in my production environment since I was to chicken.

NOTE : I have taken some of the msdn references and also JustGeeks blog spot for the references for the solutions mentioned above and changed as per my personal experience on the same.

Thank you !!!