Ultimate plugins not loaded or IDE fails to start after downgrading: com.intellij.modules.ultimate is disabled

Problem

An IntelliJ IDEA version 2025.1 or earlier misbehaves after a newer IDE from the unified distribution (2025.2 or later) has run on the same machine. Two variants occur, depending on the older version.

Variant 1: version 2024.3 or earlier does not start

Startup stops at a Start Failed dialog:

com.intellij.ide.plugins.PluginManagerCore$EssentialPluginMissingException: Missing essential plugins: com.intellij (platform prefix: null)
	at com.intellij.ide.plugins.PluginManagerCore.initializePlugins(PluginManagerCore.java:698)
	at com.intellij.ide.plugins.PluginManagerCore.initializeAndSetPlugins(PluginManagerCore.java:979)
	at com.intellij.ide.plugins.PluginDescriptorLoader$scheduleLoading$pluginSetDeferred$1.invokeSuspend(PluginDescriptorLoader.kt:403)

The same exception also appears as a Suppressed: entry beneath java.lang.IllegalArgumentException: Missing extension point: com.intellij.flsConfigurationProvider in container Application (containerState PRE_INIT).

Variant 2: version 2025.1 starts, but no Ultimate feature works

The IDE launches and the license is in order, yet every Ultimate-only plugin stays inactive:

• Settings | Plugins shows Spring, Spring Boot, Spring Cloud, and Spring Data as Not loaded.
• Spring Boot run configurations are grouped under Unknown in Run/Debug Configurations and cannot be started.
• Database Tools and SQL, Kubernetes, Diagrams, CSS, Flyway and the other bundled Ultimate plugins are equally unavailable.
• idea.log carries one line per bundled Ultimate plugin:

The Kubernetes (id=com.intellij.kubernetes, path=/Applications/IntelliJ IDEA.app/Contents/plugins/clouds-kubernetes) plugin Requires plugin 'com.intellij.modules.ultimate' to be enabled
The Database Tools and SQL (id=com.intellij.database, path=/Applications/IntelliJ IDEA.app/Contents/plugins/DatabaseTools) plugin Requires plugin 'com.intellij.modules.ultimate' to be enabled
The Diagrams (id=com.intellij.diagram, path=/Applications/IntelliJ IDEA.app/Contents/plugins/uml) plugin Requires plugin 'com.intellij.modules.ultimate' to be enabled

Signs that separate both variants from a damaged installation or a license problem

• Reinstalling the older IDE does not help, whether through JetBrains Toolbox or a standalone installer.
• Restoring a known-good backup of the older installation does not help.
• Replacing the boot JDK or the bundled JetBrains Runtime does not help.
• Deleting the configuration and cache directories of the newer version does not help — the entry has already been written to the older version's configuration directory.
• File | Invalidate Caches does not help.
• Enabling the plugins in Settings | Plugins, one by one or through the Enable required plugins link, does not help.
• The license needs no repair. Help | About reporting You have a perpetual fallback license for this version. together with Subscription expired on <date>. is the expected state for a perpetual fallback license, and re-activating with an offline activation code does not change the outcome.
• All operating systems are affected.

A common route into this state is a perpetual fallback license: the subscription expires, the current IDE starts in free mode as a result, and the older fallback version stops working. Fallback license: can I use an older version? covers which versions a fallback license grants.

Cause

IntelliJ IDEA 2025.2 and later ship as a unified distribution. Without an active subscription the IDE runs in free mode and adds com.intellij.modules.ultimate to disabled_plugins.txt in its configuration directory. A version 2025.1 or earlier that imports this configuration reads the same entry, and the effect differs by version:

• 2024.3 and earlier treat the core com.intellij plugin as missing and stop during plugin initialization.
• 2025.1 starts, then skips every bundled plugin that declares a dependency on com.intellij.modules.ultimate, which is the whole Ultimate feature set.

The entry is stored in the configuration directory, not in the installation directory. Reinstalling the IDE or restoring the installation folder leaves it untouched, which is why neither step changes the outcome. Deleting the newer version's configuration and caches removes the source of the import, not the entry already written to the older version's file.

Resolution

1. Close the affected IDE.
2. Open disabled_plugins.txt in the configuration directory of the affected version.
3. Delete the line com.intellij.modules.ultimate and save the file.
4. Start the IDE.

Plugins reported as Not loaded load on the next start, and run configurations that appeared under Unknown resolve back to their original type once indexing finishes.

The configuration directory per operating system:

<product><version> resolves to a name such as IntelliJIdea2023.2 or IntelliJIdea2025.1. The exact folder name can be confirmed by listing the JetBrains directory. Directories used by the IDE to store settings, caches, plugins and logs describes how the name is composed.

If disabled_plugins.txt does not exist in that directory, or does not contain com.intellij.modules.ultimate, this article does not apply.