Installer sometimes gives "Drupal already installed" message even if install failed

Well it reads:

To start over, you must empty your existing database and copy default.settings.php over settings.php.

That does seem clear.

Just to be clear, there is not anything obviously wrong with the error messages. I am removing the novice tag so people don't start work on this. I linked a related issue that covers part of what is in the issue summary.

Guys,

I have same issue. Actually it needs me to install the existing site on my local machine for which i did git clone and get the dump of database and imported it into my local mysql server. Now i have changed the variables in setting.php accordingly like database name, host, password etc. Now it should work and should show me the home page of site. But unfortunately it is always redirecting me to the core/install.php page and shows me same message "Drupal already installed" like screen shot is attached by someone above.
Please help me, i spend lot of time on it. FYI, i don't want to empty my database and then reinstall the site.

Thank you in advance,

Hello,
same problem as 10
drupal 8.5.5
a charitable soul,
thank you in advance for any help

This issue is now reproducible in latest dev version which is blocking from fixing issues on 8.7.x. Issue occurs even if minimal install profile is used not just for standard install profile.

I have been suffering from this problem for a week now.

Full days to try to understand, and see what I would have done wrong.
No solution, it breaks the mood!

This does not meet the criteria of a major bug but I'm tagging it "usability" if reworded messages would increase understanding.

I had to uninstall Webprofiler and then everything works just fine. No idea exactly why but it works :)

I get this with 8.7.x. I am trying to install into an empty Postgres database. It says "Drupal already installed". When I look back in the database, cache_container has been created. It is otherwise empty.

If I click "view your existing site", I get redirected back to "Drupal already installed".

Same issue on 8.6.2
Migrating a site to live server.

All files uploaded and database imported.

Updated settings.php, tried using default.settings.php as new settings.php and it still brings me to installation page with "Drupal is already installed" message.

Same issue on 8.6.5

New site, and after enabling some module, it show me this message.

If I click "view your existing site", and try to go to admin/module, i got 'The website has encountered an unexpected error. Please try again later.'

The only way to get a site working is to manually go to /update.php.

But after that, almost every module activation it show me this message "Drupal already installed ......".

I'm sporadically getting this.
Like #15, I suspect this may be associated with webprofiler.
Some excerpts from corresponding log entries below...

Warning: session_write_close(): Failed to write session data with "Drupal\Core\Session\WriteSafeSessionHandler" handler in Symfony\Component\HttpFoundation\Session\Storage\NativeSessionStorage->Symfony\Component\HttpFoundation\Session\Storage\{closure}() (line 240 of /app/vendor/symfony/http-foundation/Session/Storage/NativeSessionStorage.php) #0 /app/web/core/includes/bootstrap.inc(587): _drupal_error_handler_real(2, 'session_write_c...', '/app/vendor/sym...', 244, NULL) #1 /app/vendor/symfony/http-foundation/Session/Storage/NativeSessionStorage.php(240): _drupal_error_handler(2, 'session_write_c...', '/app/vendor/sym...', 244) #2 [internal function]: Symfony\Component\HttpFoundation\Session\Storage\NativeSessionStorage->Symfony\Component\HttpFoundation\Session\Storage\{closure}(2, 'session_write_c...', '/app/vendor/sym...', 244, Array) #3 /app/vendor/symfony/http-foundation/Session/Storage/NativeSessionStorage.php(244): session_write_close() #4 /app/web/core/lib/Drupal/Core/Session/SessionManager.php(198): Symfony\Component\HttpFoundation\Session\Storage\NativeSessionStorage->save() #5 /app/vendor/symfony/http-foundation/Session/Session.php(196): Drupal\Core\Session\SessionManager->save() #6 /app/web/core/lib/Drupal/Core/StackMiddleware/Session.php(60): Symfony\Component\HttpFoundation\Session\Session->save() #7 /app/web/core/lib/Drupal/Core/StackMiddleware/KernelPreHandle.php(47): Drupal\Core\StackMiddleware\Session->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #8 /app/web/core/modules/page_cache/src/StackMiddleware/PageCache.php(106): Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #9 /app/web/core/modules/page_cache/src/StackMiddleware/PageCache.php(85): Drupal\page_cache\StackMiddleware\PageCache->pass(Object(Symfony\Component\HttpFoundation\Request), 1, true) #10 /app/web/core/modules/ban/src/BanMiddleware.php(50): Drupal\page_cache\StackMiddleware\PageCache->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #11 /app/web/core/lib/Drupal/Core/StackMiddleware/ReverseProxyMiddleware.php(47): Drupal\ban\BanMiddleware->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #12 /app/web/modules/contrib/devel/webprofiler/src/StackMiddleware/WebprofilerMiddleware.php(38): Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #13 /app/web/core/lib/Drupal/Core/StackMiddleware/NegotiationMiddleware.php(52): Drupal\webprofiler\StackMiddleware\WebprofilerMiddleware->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #14 /app/vendor/stack/builder/src/Stack/StackedHttpKernel.php(23): Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #15 /app/web/core/lib/Drupal/Core/DrupalKernel.php(693): Stack\StackedHttpKernel->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #16 /app/web/index.php(19): Drupal\Core\DrupalKernel->handle(Object(Symfony\Component\HttpFoundation\Request)) #17 {main}.

Unable to store the profiler information.

Warning: Error while sending QUERY packet. PID=9061 in Drupal\Core\Database\Statement->execute() (line 59 of /app/web/core/lib/Drupal/Core/Database/Statement.php) #0 /app/web/core/includes/bootstrap.inc(587): _drupal_error_handler_real(2, 'Error while sen...', '/app/web/core/l...', 59, Array) #1 [internal function]: _drupal_error_handler(2, 'Error while sen...', '/app/web/core/l...', 59, Array) #2 /app/web/core/lib/Drupal/Core/Database/Statement.php(59): PDOStatement->execute(Array) #3 /app/web/core/lib/Drupal/Core/Database/Connection.php(631): Drupal\Core\Database\Statement->execute(Array, Array) #4 /app/web/core/lib/Drupal/Core/Database/Driver/mysql/Connection.php(358): Drupal\Core\Database\Connection->query('INSERT INTO {wa...', Array, Array) #5 /app/web/core/lib/Drupal/Core/Database/Driver/mysql/Insert.php(32): Drupal\Core\Database\Driver\mysql\Connection->query('INSERT INTO {wa...', Array, Array) #6 /app/web/core/modules/dblog/src/Logger/DbLog.php(78): Drupal\Core\Database\Driver\mysql\Insert->execute() #7 /app/web/modules/contrib/dblog_filter/src/Logger/DBLogFilter.php(63): Drupal\dblog\Logger\DbLog->log(4, 'Unable to store...', Array) #8 /app/web/core/lib/Drupal/Core/Logger/LoggerChannel.php(127): Drupal\dblog_filter\Logger\DBLogFilter->log(4, 'Unable to store...', Array) #9 /app/vendor/psr/log/Psr/Log/LoggerTrait.php(86): Drupal\Core\Logger\LoggerChannel->log(4, 'Unable to store...', Array) #10 /app/vendor/symfony/http-kernel/Profiler/Profiler.php(106): Drupal\Core\Logger\LoggerChannel->warning('Unable to store...', Array) #11 /app/web/modules/contrib/devel/webprofiler/src/EventSubscriber/ProfilerSubscriber.php(104): Symfony\Component\HttpKernel\Profiler\Profiler->saveProfile(Object(Symfony\Component\HttpKernel\Profiler\Profile)) #12 /app/web/modules/contrib/devel/webprofiler/src/EventDispatcher/TraceableEventDispatcher.php(76): Drupal\webprofiler\EventSubscriber\ProfilerSubscriber->onKernelFinishRequest(Object(Symfony\Component\HttpKernel\Event\FinishRequestEvent), 'kernel.finish_r...', Object(Drupal\webprofiler\EventDispatcher\TraceableEventDispatcher)) #13 /app/vendor/symfony/http-kernel/HttpKernel.php(210): Drupal\webprofiler\EventDispatcher\TraceableEventDispatcher->dispatch('kernel.finish_r...', Object(Symfony\Component\HttpKernel\Event\FinishRequestEvent)) #14 /app/vendor/symfony/http-kernel/HttpKernel.php(193): Symfony\Component\HttpKernel\HttpKernel->finishRequest(Object(Symfony\Component\HttpFoundation\Request), 1) #15 /app/vendor/symfony/http-kernel/HttpKernel.php(173): Symfony\Component\HttpKernel\HttpKernel->filterResponse(Object(Drupal\Core\Render\HtmlResponse), Object(Symfony\Component\HttpFoundation\Request), 1) #16 /app/vendor/symfony/http-kernel/HttpKernel.php(68): Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object(Symfony\Component\HttpFoundation\Request), 1) #17 /app/web/core/lib/Drupal/Core/StackMiddleware/Session.php(57): Symfony\Component\HttpKernel\HttpKernel->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #18 /app/web/core/lib/Drupal/Core/StackMiddleware/KernelPreHandle.php(47): Drupal\Core\StackMiddleware\Session->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #19 /app/web/core/modules/page_cache/src/StackMiddleware/PageCache.php(106): Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #20 /app/web/core/modules/page_cache/src/StackMiddleware/PageCache.php(85): Drupal\page_cache\StackMiddleware\PageCache->pass(Object(Symfony\Component\HttpFoundation\Request), 1, true) #21 /app/web/core/modules/ban/src/BanMiddleware.php(50): Drupal\page_cache\StackMiddleware\PageCache->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #22 /app/web/core/lib/Drupal/Core/StackMiddleware/ReverseProxyMiddleware.php(47): Drupal\ban\BanMiddleware->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #23 /app/web/modules/contrib/devel/webprofiler/src/StackMiddleware/WebprofilerMiddleware.php(38): Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #24 /app/web/core/lib/Drupal/Core/StackMiddleware/NegotiationMiddleware.php(52): Drupal\webprofiler\StackMiddleware\WebprofilerMiddleware->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #25 /app/vendor/stack/builder/src/Stack/StackedHttpKernel.php(23): Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #26 /app/web/core/lib/Drupal/Core/DrupalKernel.php(693): Stack\StackedHttpKernel->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #27 /app/web/index.php(19): Drupal\Core\DrupalKernel->handle(Object(Symfony\Component\HttpFoundation\Request)) #28 {main}.

Hi there, i am running Drupal 8.7.3, the most recent version. I installed Gutenberg and everything was going smooth for the most part.

I just installed Devel module and now when i try to go to the Uninstall screen, I keep getting the /core/install.php page.

It says "To start over, you must empty your existing database and copy default.settings.php over settings.php.
To upgrade an existing installation, proceed to the update script.
View your existing site."

I've tried all of these options except the first one because I do not want to start over.

I tried the update script and rebuild script...I keep getting this error.

I'm new to Drupal, but so far it has been like everything little I do, I'm running into a problem here and there.

I tried clearing my cache too. Any suggestions?

I am having the same issue.

I am having the same issue.

I am trying to install the Json API. when i try to enable the Json API module, i am informed that i need to install the serialization module as a requirement. After installing the serialization module, i get the "Drupal already installed" message, i dont know if this has to do with core or with the serialization module.

Any Advice
I am on a windows 10 pc , using wampserver.

I have found the solution.

This can be fixed by increasing the size of
your max_post_size in your php.ini file and increasing the max_allowed_packet in your my.ini as well as post_max_size to about 128 mb or more

I think this thread includes a few different reasons why this is occurring but if you have just recently installed/enabled json api module then the fix is here, https://www.drupal.org/project/jsonapi/issues/3059472#comment-13236938.

#24 worked for me

I have found the solution.

This can be fixed by increasing the size of
your max_post_size in your php.ini file and increasing the max_allowed_packet in your my.ini as well as post_max_size to about 128 mb or more

#24 worked for me too
Thanks

#24 Worked for me too.
Tks!

I was running into this error message recently when attempting to create a multisite environment.

Example "sites" folder structure:

default (folder)
website.com (folder)
website2.com (folder)
example.sites.php
development.services.yml
example.settings.local.php

I had overlooked editing and renaming example.sites.php to include the names of the other folders (website.com and website2.com).

Once I did that the "drupal already installed" messages disappeared.

Another apparent trigger for this nondescript error is when you have a MySQL version that is below the minimum requirement. (For example, I got this error when trying to install Drupal 9 with MySQL 5.6...the minimum version requirement is 5.7.8 now). Using the minimum-compatible MySQL version fixed the issue.

I have encountered similar problem.
I have an existing website where I was trying to login. After providing login details when I click login button it redirect me to /core/install.php page and I get the bellow error message.

#24 works.
In my case, I tried to activate 6 modules (commerce_product_bundle and its dependent modules),
then the execution was time over 120s, which longer than the settings in php.ini file.
So the execution stopped and broke the whole system.

Hi All,
I am using drupal 9.1.0. I have installed menu_item_extras module my site goes down i have uninstalled module using drush. now i am getting below error.
To start over, you must empty your existing database and copy default.settings.php over settings.php.
To upgrade an existing installation, proceed to the update script.

Thanks

@Abhilash001 -- you posted this question here and in the Discuss section of a Documentation page... Neither place is a good way to get support. Please see
https://www.drupal.org/support
to find a support channel where you are more likely to get help.

#24 worked for me

There hasn't been any discussion here for 4 years so perhaps this is no longer a problem?

This does need steps to reproduce, so tagging. Since we need more information to move forward with this issue, I am setting the status to Postponed (maintainer needs more info). If we don't receive additional information to help with the issue, it may be closed after three months.

Thanks!

Since there hasn't been a follow up going to close out, if still an issue in D11 please reopen

Thanks all!