UPDATED with FPA output ( see forum thread https://forum.joomla.org/viewtopic.php?f=803&t=967064&p=3547996#p3547996 )

I assume that you have mysql 5.7 or newer.

There is a problem with zero dates.
If you replace (in phpmyadmin) the zero dates 0000-00-00 00: 00: 00 by 1000-00-00 00: 00: 00 in the #__ modules table, then the modules should appear.

This PR may help too #21901

Thanks!
running SQL 8…

but setting all the zero dates starting with 1000 doesn't improve the situation here... still no modules or menus in either front or backend.

**Here is a clue, perhaps... (??)

pasted URL for check database, it sent back this:**

`Table 'j40a5_modules' has the wrong type or attributes for column 'content' with type TEXT. (From file 4.0.0-2018-03-05.sql.)

Table 'j40a5_finder_terms' has the wrong type or attributes for column 'language' with type CHAR(7). (From file 4.0.0-2018-04-14.sql.)

Table 'j40a5_finder_terms_common' has the wrong type or attributes for column 'language' with type CHAR(7). (From file 4.0.0-2018-04-14.sql.)

Table 'j40a5_finder_tokens' has the wrong type or attributes for column 'language' with type CHAR(7). (From file 4.0.0-2018-04-14.sql.)

Table 'j40a5_finder_tokens_aggregate' has the wrong type or attributes for column 'language' with type CHAR(7). (From file 4.0.0-2018-04-14.sql.)

Table 'j40a5_finder_links' has the wrong type or attributes for column 'language' with type CHAR(7). (From file 4.0.0-2018-04-14.sql.)

18 database changes were checked.

41 database changes did not alter table structure and were skipped.`

Incidentally, my (perfectly running) 3.8.13 install (on the same server,using MySQL8) also reports some db problems (but in 3.8.13 the functionality of the front and back end are both 100% perfect)... here are the 3.8.13 errors:

`Table 'j38_languages' has the wrong type or attributes for column 'sitename' with type VARCHAR(1024). (From file 2.5.0-2012-01-14.sql.)

Table 'j38_associations' has the wrong type or attributes for column 'id' with type INT(11). (From file 3.0.3.sql.)
Table 'j38_user_profiles' has the wrong type or attributes for column 'profile_value' with type TEXT. (From file 3.3.4-2014-08-03.sql.)

Table 'j38_redirect_links' has the wrong type or attributes for column 'old_url' with type VARCHAR(2048). (From file 3.5.0-2016-03-01.sql.)

Table 'j38_redirect_links' has the wrong type or attributes for column 'new_url' with type VARCHAR(2048). (From file 3.5.0-2016-03-01.sql.)

Table 'j38_redirect_links' has the wrong type or attributes for column 'referer' with type VARCHAR(2048). (From file 3.5.0-2016-03-01.sql.)

Table 'j38_redirect_links' has the wrong type or attributes for column 'new_url' with type VARCHAR(2048). (From file 3.6.0-2016-04-06.sql.)

Table 'j38_newsfeeds' has the wrong type or attributes for column 'link' with type VARCHAR(2048). (From file 3.6.3-2016-08-15.sql.)

Table 'j38_extensions' has the wrong type or attributes for column 'enabled' with type TINYINT(3). (From file 3.7.0-2016-11-04.sql.)

Table 'j38_modules' has the wrong type or attributes for column 'content' with type text. (From file 3.7.0-2016-11-27.sql.)

Table 'j38_ucm_content' has the wrong type or attributes for column 'core_body' with type mediumtext. (From file 3.7.0-2017-01-08.sql.)

Table 'j38_ucm_content' has the wrong type or attributes for column 'core_params' with type text. (From file 3.7.0-2017-01-08.sql.)

Table 'j38_ucm_content' has the wrong type or attributes for column 'core_images' with type text. (From file 3.7.0-2017-01-08.sql.)

Table 'j38_ucm_content' has the wrong type or attributes for column 'core_urls' with type text. (From file 3.7.0-2017-01-08.sql.)

Table 'j38_ucm_content' has the wrong type or attributes for column 'core_metakey' with type text. (From file 3.7.0-2017-01-08.sql.)

Table 'j38_ucm_content' has the wrong type or attributes for column 'core_metadesc' with type text. (From file 3.7.0-2017-01-08.sql.)

Table 'j38_categories' has the wrong type or attributes for column 'description' with type mediumtext. (From file 3.7.0-2017-01-09.sql.)

Table 'j38_categories' has the wrong type or attributes for column 'params' with type text. (From file 3.7.0-2017-01-09.sql.)

Table 'j38_finder_links' has the wrong type or attributes for column 'description' with type text. (From file 3.7.0-2017-03-19.sql.)`

PS: the Fix button in J3.8.13 has no effect on the above errors...

UPDATED: I once again tried the update

UPDATE #__modules SET checked_out_time = '1000-01-01 00:00:00', publish_up = '1000-01-01 00:00:00', publish_down = '1000-01-01 00:00:00';

And the back end IS WORKING this time ( very odd, as I had run that before to no avail..) As is the front end. Maybe just because I had applied the Alpha 6 update??

Incidentally, the same db errors are noted as above ( for J4) and "Fix" button doesn't fix them...

Set to "closed" on behalf of @franz-wohlkoenig by The JTracker Application at issues.joomla.org/joomla-cms/22974

closed in favor of #24151