Manual install of subtheme results in white screen.

@hcanning
Can you share error which are on "Recent log messages" page(/admin/reports/dblog)?
May be you did not rename all templates and functionals.

Hi @hcanning ,

I just reproduce your issue on my machine, I successfully installed it and set as default theme, Also I'm using the same Drupal version 9.5.10.

However, What i think that you missed is some minor spelling mistake on renaming the templates and functionals things.
Please refer the attached screens for more clarity.

For example,
If i give my subtheme named as dummy subtheme , so please make sure that you've given the name correctly to other files apart from the functional thing.
i.e..., dummytheme.info.yml , dummysubtheme.theme , dummysubtheme.libraries.yml etc
Let me know in case of any queries , happy to assist you further.
Hope it helps, Thanks.

Hi,
So if it helps others. On testing the Barrio them on day one, I used the subtheme in place at '[mysite1]/themes/bootstrap_barrio/subtheme' , added template,layout and content files etc...and built a sample webpage. Yesterday I tried to copy that particular subtheme over to '[mysite1]/themes/[mycustomtheme]'` following the how → . I followed it exactly and triple checked everything. I'd recommend changing 1 line in the how-to "Copy the subthemefolder on your /themes/custom directory." as it suggest you have to create the subtheme in a folder called custom e.g. '[mysite1]/themes/custom/subtheme/[mycustomtheme]'

Anyway I got the white screen of death and no error logs that pointed to a fix. Anyway THE SOLUTION for me was to reinstall the original Barrrio theme fresh on another server and use (install and set as default) the fresh 'themes/bootstrap_barrio/subtheme' from that , place it at '[mysite1]/themes/[mycustomtheme] and restore the template, layout, content and general asset files I had from the original installation.

Works now if others have the same problem. I'm a newbie at Drupal so that was my fix.

Thanks

@hcanning
If you can provider errors then it will help to understand your problem.

You may check the errors following below steps -
1. Enable "Database logging" module.
2. Navigate to admin toolbar -> Reports -> Recent log messages

Check the errors and share screenshots of the errors.

@hcanning
Do you need more support on this ticket?