You won't be able to convert Donation pages to Donation (v2) pages for a site if:

• The nation is syncing theme files with Dropbox. To allow our converter to make necessary changes to your theme files, you'll need to disconnect Dropbox until you've finished converting.
• The theme has drafted changes to theme.scss. This means you (or your designer) has pending customizations to your theme that we don't want to overwrite with necessary changes. To proceed, get someone with the right permission to discard or publish the changes. 
• The site has a v1 theme. To resolve this, switch your site to any of our updated custom themes or contact [email protected] for assistance.