Here are a few tips for migrating a site to Shifter.
1. Update all plugins or themes
Shifter automatically keeps your WordPress install current with the latest version. However, plugins and themes must be updated manually. Older plugins or themes might cause failure during artifact creation as well as missing or corrupted posts and pages in the artifact.
Never forget to update plugins and themes to the latest version before migrating your site to Shifter.
2. Remove WordPress Caching Plugin
Are you running a caching plugin for WordPress? Using caching Plugins can be helpful on traditional hosting platforms but they aren't needed here. Shifter generates static versions of each page of your site and caching plugins can conflict with that process.
Some common WordPress Caching Plugins to disable or remove when used with Shifter:
SNS Count Cache
WP Super Cache
WP Fastest Cache
W3 Total Cache
3. Remove unused themes and plugins
Unused plugins or themes could be creating a timeout during the migration process.
Check to see if there are any unused plugins or themes that could be causing problems and remove them completely.
4. Check PHP compatibility with plugins or themes
Shifter is running on PHP 7.2. Check and make sure all of your plugins or themes work on this version of PHP with the following plugins.