How to make the 'Module Updates' report available again? I have a 7.18 Drupal site running since a long time without updates. The update manager was deactivated since then as well.

Now I had to move the site to another server and after reactivating the update manager, it does not work properly. I have the status message that there are updates available, but the paths admin/reports/updates or admin/reports/updates/update only lead to the reports overview page.

Does anyone have a hint about how to fix this?
Here is a list of items to check:


Make sure core module update (= Update Manager) is enabled.
Clear all caches: if you get a WSOD while doing so, it indicates memory shortage.
Try running update.php: if you get a Fatal error like "Allow memory size of ... bytes exhausted", it indicates memory shortage.
Verify if it is a memory shortage issue: try increasing the memory a bit to check if there is any difference.