Export/import contents only from Multisite sites to clean Multisite install

Review the documentation on moving WordPress. There is a section on the specific issues involved in moving multisite.

Can I just use the WP export/import plug-ins to do one site at a time? What about the URLS?

I’m unsure how well those work with multisite. They supposedly update URLs accordingly, but TBH I’ve run into issues with such tools on occasion. They’re great when they work, which is most of the time. They are extremely frustrating when they fail. I generally rely on manual migration as described in the above link. I use the Interconnect/it database script to update the URLs.

I’m unsure how successful a piecemeal migration will be in an attempt to clean things up. In theory you should be able to make a new clean installation and selectively migrate only the content related tables. But many tables are interrelated. If you migrate one but not the ones that are related it’s going to become a big mess.

You may be better off cleaning the existing installation as best you can. No doubt there will be left over unused cruft despite your best efforts, but it may not have much impact as long as the broken and out dated elements are deactivated and removed.

OTOH, there’s not much harm in trying a piecemeal migration beyond lost time. Don’t abandon the original site until you’re 100% sure your efforts were successful. Keep frequent incremental backups of the new DB before each change so you can easily step back if anything goes wrong. You still should attempt to clean up the current site as best you can prior to migration.

Thank you for your input! I appreciate it immensely. I wanted to make sure I wasn’t going to do something that was an absolute no go.

I’ve not seen the documentation you linked, that’s a big help. Exactly what I need! After I read it I’m going to try to it import the content on the main site and one subsite to see what happens.

Side note:

The main site is 80 pages. Among other things, like broken or unnecessary plug-ins, the many shortcodes some are not working and I don’t know which plug-ins go with them, too many plug-ins plus many install and unistalls…

I have created versions of the subsites in the past that did not delete – with overlapping URLS. Sometimes an old version will come up when I hit the network link. I can see the folders in the files but the sites are not listed in the network admin.

If you have shortcodes that are not getting expanded into content and you’re unable to identify which plugin they belong to, you don’t have much choice other than to either remove them or replace them with an alternatives.

If you have terminal access or download all the /plugins/ files, you could search for the shortcode’s PHP declaration to identify which plugin it belongs to. Use grep (Linux) or findstr (Windows) to do a full text recursive search for the shortcode’s name. The name occurring in an add_shortcode() call will be what you’re looking for. Assuming the plugin is still installed, even though deactivated, where the found add_shortcode() call occurs tells you which plugin it belongs to. You could then decide if you want to reactivate it or not.

Having remnant file system elements relating to something that has been deleted in WP is not that uncommon. Some file system settings prevent PHP from being able to fully remove certain elements. If you are sure the files and folders are obsolete you can manually delete them or just not migrate them. As always, it’s not a bad idea to maintain a backup version prior to deletion. The backup can be deleted after some time when you’re sure the files are no longer needed.