I am proposing an issue on IIS 8 not being compatible with Drupal 8. According to the Drupal.org System Requirements, "Drupal core will work with IIS 5, IIS 6, or IIS 7 if PHP is configured correctly" (February 9, 2017). Drupal's system requirements does not state that IIS 8 runs with Drupal. I have tested running Drupal 8, specifically 8.2.6 (8.2.7, & 8.2.0) on IIS 8. When trying to install Drupal 8.2.6 the following occurred: after selecting 'save and continue' from 'database configuration', I was redirected back to the 'database configuration' page. There were no errors displayed, just being redirected back without having the chance to install. Therefore it looks like a compatibility issue among IIS 8 and Drupal 8.2.6. Otherwise the program would have been able to install proficiently as Drupal 7 installs with IIS 8 (using My SQL and MSSQL).

Below are links of other users that experience the same issue using Drupal 8 with IIS8.


The link below displays a user constantly getting redirected to the log in page.

The link below displays the System Requirement.

I have seen a user that installed Drupal 8 using IIS 7 (with no errors). I just needed to report this issue because it is a new install in which, I tested among multiple variations. It should not occur.

The way I configured Drupal, and IIS 8 was the same as the link below. Only difference is I used IIS 8, and the tutorial uses IIS 7


Thank you,


ricky93 created an issue. See original summary.

cilefen’s picture

Component: config.module » base system
Category: Support request » Bug report
Status: Needs review » Active
Issue tags: -iis7, -drupal8, -Configuration system, -database
Related issues: +#2856436: Using IIS for Drupal and My SQL

No errors display, but are any errors being logged by PHP or by the database server?

ricky93’s picture

There are no errors within the database server or logged by PHP when having error display 'on' in pnp.ini. After Drupal redirected me back to the 'Database Configuration' (ignoring the installation), I checked the database tables, seeing only 21 tables under the database (tables ended at the dbo.users_filed_data table).

I have tested installing Drupal 8 with IIS8 with the following:

  • two different servers containing the same result.
  • My SQL and SQL containing the same result.
  • Drupal 8.2.6, 8.2.0, 8.1 containing the same result.
  • Drupal 7 different result, only one that succeeded
  • Debug the files using php storm, I did not see errors

If the file were to be a set up issue, then Drupal would not been able to install after about the 6th try. I literally had to remove settings.php/and files folder. Redoing the process multiple times until installation appears should not occur. If there were no issue with IIS8 then Drupal 8.2.6 would have been installed the first try, not 6th. It would be beneficial if someone can look into this issue.

cilefen’s picture

What is the value of max_allowed_packet in MySQL?

ricky93’s picture

The max_allowed_packet is 4M. This applies to mysqld.

cilefen’s picture

Increase it.

It may be necessary to set the system variable max_allowed_packet to at least 16M.


I don't actually know what's going on with this system. You said you checked the database server logs and I am pretty sure it would log this kind of problem. But definitely increase max_allowed_packet.