Missing Workflows after Migration
If you find the default OOTB workflows missing after migration from SharePoint 2007 to Sharepoint 2010, the following steps may help restore them:
1) Open the root of the site collection in SharePoint Designer 2010
2) In the Navigation section, click on All Files, then click _catlogs
3) Check for a folder named "wfpub" and if it exists right click on it and delete it
4) Run the following PowerShell for the site collection having the issue:
$site = Get-SPSite https://root-site-collection-url
Disable-SPFeature -url $site.URL -Identity Workflows -Confirm:$false
Disable-SPFeature -url $site.URL -Identity OffWFCommon -Confirm:$false
Enable-SPFeature -url $site.URL -Identity OffWFCommon
Enable-SPFeature -url $site.URL -Identity Workflows