TYPO3 v9 has reached its end-of-life September 30th, 2021 and is not maintained by the community anymore. Looking for a stable version? Use the version switch on the top left.
You can order Extended Long Term Support (ELTS) here: TYPO3 ELTS.
With Command Line (Recommended)¶
In a composer installation execute:
In a non-composer installation execute:
php ./typo3/sysext/core/bin/typo3 referenceindex:update
referenceindex:update 2> /dev/null to suppress the progress output
(e.g. when the command is executed by a cronjob).
Without Command Line¶
Still in your old TYPO3 version, go to the "System" > "DB check" module and use the "Check and update global reference index" function.
Click on "Update reference index" to update the reference index. In case there is a timeout and you do not have CLI access (see above) you might have to run the update multiple times.