Deleted mime type - how to resolve while migration

i had erroneously deleted a mimetype markdown_to_html . it has never been used in the site. i now face a failed migration due to the same. any suggestions on how to resolve.

Ran upgrade step: Miscellaneous
Upgrade aborted. Error:
Traceback (most recent call last):
File "/opt/plone/buildout-cache/eggs/Products.CMFPlone-5.2.4-py2.7.egg/Products/CMFPlone/", line 292, in upgrade
File "/opt/plone/buildout-cache/eggs/Products.GenericSetup-2.1.1-py2.7.egg/Products/GenericSetup/", line 168, in doStep
File "/opt/plone/buildout-cache/eggs/", line 155, in move_markdown_transform_settings_to_registry
extensions = pt.markdown_to_html._config.get('enabled_extensions') or
AttributeError: 'RequestContainer' object has no attribute 'markdown_to_html'
End of upgrade path, main migration has finished.
The upgrade path did NOT reach current version.
Migration has failed

Version Overview

Plone 5.2.4
Zope 4.5.5
Python 2.7.17 (default, Feb 27 2021, 15:10:58) [GCC 7.5.0]

Hello @ sudhan77,
Didn't you make a recent backup of the site before the accidental deletion?
If so, wouldn't it be easier to start from this backup?
Maybe I didn't quite understand the context?


yes, thankyou. i actually realised it later. and restored the backup.

Another way to reset a mimetypes registry is to create a second parallel vanilla plone site, then in ZMI delete the registry in your original site, copy the registry from the vanilla site and insert it in the original site.

1 Like

thanks. i started afresh from a backup restore. resolved the upgrade and migration from 5.0.5 to 5.2.4. Of course for the easier site. the difficult ones will deal another day. too challenging for non-developers. I have understood the issues involved.

Indeed, it can get complex with this domain of problems. If in trouble, do not hesitate to ask in this forum!