forgot to add… I have to wait awhile – 10+minutes to hours… Every time it’s different.
So you’re actively using the admin area, then you are suddenly redirected to install.php? The only reason that could happen is when WP cannot find its tables in its database. The database connection is OK, otherwise you’d get a error message. Obviously the tables exist or you’d never get to the dashboard to start with.
Unfortunately, the intermittent nature of this problem makes it difficult to diagnose and repair. I suspect an issue with the database server itself; however, it is plausible there’s a problem with your installation. If it’s your installation and not the server, it’s most likely due to your theme or one of your plugins. The usual technique of debugging WP involves switching themes and deactivating plugins. This is not so easy if you keep getting the installation dialog. To work around this, access your installation’s files via FTP or your hosting file manager. Go to /wp-content/themes/ and locate the directory that contains your theme. Rename it. WP will then fail to find your theme and use another.
Next go back to /wp-content/ and rename the /plugins/ directory. This will prevent WP from finding your plugins and will thus deactivate all of them. If you are able to access your dashboard without getting the installation dialog now, then the database server is not at fault and the problem is in your theme or one of your plugins. Then the question is which one?
Next restore the /plugins/ and your theme’s normal directory names. In the WP back end, switch back to your normal theme and begin reactivating plugins. Once you are back to getting the installation dialog, the last activated module would be the most likely cause. However, due to the intermittent nature of the problem, you may need to repeat this process a number of times before you can accurately isolate the problem module.
OTOH, if the problem persists with a different theme and no plugins active, then the issue is most likely with the database server itself. Seek the assistance of your host’s tech support in this situation.
@bcworkz has covered the theme/plugin and database server angles well.
Before the theme/plugin isolation process, I’d suggest enabling debug logging first, it’ll tell you exactly what’s failing at the moment it happens.
Add this to wp-config.php above the /* That's all, stop editing! */ line:
define( 'WP_DEBUG', true );
define( 'WP_DEBUG_LOG', true );
define( 'WP_DEBUG_DISPLAY', false );
Next time it redirects to install.php, check /wp-content/debug.log immediately. Given the intermittent, self-resolving pattern, this looks like database server instability on the host side, the log will confirm it and give you something concrete to send to your host’s support.
