# Problem after installation 5.2.6 **URL:** \ **Category:** Configuration/Setup\ **Created:** [September 3, 2026, 11:12am UTC](https://community.bluespice.com/t/problem-after-installation-5-2-6/440 "2026-09-03T11:12:48Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![Lasse](https://avatars.discourse-cdn.com/v4/letter/l/96bed5/32.png) [@Lasse](https://community.bluespice.com/u/Lasse)\ **Post date:** [September 3, 2026, 11:12am UTC](https://community.bluespice.com/t/problem-after-installation-5-2-6/440/1 "2026-09-03T11:12:48Z")
**Describe the issue / Steps to reproduce:** My Problem is that I get some enhanced Sidebar error when I am Finished with the installation. **Expected behavior:** I thought I would get an Login page. **What was the error message/error log?** MediaWiki internal error. Original exception: [82b08ba2ff659d17b87ed57b] /wiki TypeError: BlueSpice\Discovery\EnhancedSidebar\Parser::\_\_construct(): Argument #1 ($revision) must be of type MediaWiki\Revision\RevisionRecord, null given, called in /app/bluespice/w/skins/BlueSpiceDiscovery/src/Component/EnhancedSidebarContainer.php on line 151 Backtrace: from /app/bluespice/w/skins/BlueSpiceDiscovery/src/EnhancedSidebar/Parser.php(53) #0 /app/bluespice/w/skins/BlueSpiceDiscovery/src/Component/EnhancedSidebarContainer.php(151): BlueSpice\Discovery\EnhancedSidebar\Parser-\>\_\_construct() #1 /app/bluespice/w/skins/BlueSpiceDiscovery/src/Component/EnhancedSidebarContainer.php(92): BlueSpice\Discovery\Component\EnhancedSidebarContainer-\>getParserData() #2 /app/bluespice/w/skins/BlueSpiceDiscovery/src/Component/EnhancedSidebarContainer.php(80): BlueSpice\Discovery\Component\EnhancedSidebarContainer-\>buildPanels() #3 /app/bluespice/w/vendor/mwstake/mediawiki-component-commonuserinterface/src/ComponentManager.php(240): BlueSpice\Discovery\Component\EnhancedSidebarContainer-\>getSubComponents() #4 /app/bluespice/w/vendor/mwstake/mediawiki-component-commonuserinterface/src/ComponentManager.php(242): MWStake\MediaWiki\Component\CommonUserInterface\ComponentManager-\>processComponent() #5 /app/bluespice/w/vendor/mwstake/mediawiki-component-commonuserinterface/src/ComponentManager.php(185): MWStake\MediaWiki\Component\CommonUserInterface\ComponentManager-\>processComponent() #6 /app/bluespice/w/vendor/mwstake/mediawiki-component-commonuserinterface/src/ComponentManager.php(120): MWStake\MediaWiki\Component\CommonUserInterface\ComponentManager-\>init() #7 /app/bluespice/w/vendor/mwstake/mediawiki-component-commonuserinterface/includes/ServiceWiring.php(26): MWStake\MediaWiki\Component\CommonUserInterface\ComponentManager::singleton() #8 /app/bluespice/w/vendor/wikimedia/services/src/ServiceContainer.php(440): Wikimedia\Services\ServiceContainer::{closure:/app/bluespice/w/vendor/mwstake/mediawiki-component-commonuserinterface/includes/ServiceWiring.php:25}() #9 /app/bluespice/w/vendor/wikimedia/services/src/ServiceContainer.php(406): Wikimedia\Services\ServiceContainer-\>createService() #10 /app/bluespice/w/includes/MediaWikiServices.php(357): Wikimedia\Services\ServiceContainer-\>getService() #11 /app/bluespice/w/vendor/mwstake/mediawiki-component-commonuserinterface/src/Setup.php(59): MediaWiki\MediaWikiServices-\>getService() #12 /app/bluespice/w/includes/HookContainer/HookContainer.php(159): MWStake\MediaWiki\Component\CommonUserInterface\Setup-\>onBeforePageDisplay() #13 /app/bluespice/w/includes/HookContainer/HookRunner.php(983): MediaWiki\HookContainer\HookContainer-\>run() #14 /app/bluespice/w/includes/Output/OutputPage.php(3186): MediaWiki\HookContainer\HookRunner-\>onBeforePageDisplay() #15 /app/bluespice/w/includes/actions/ActionEntryPoint.php(164): MediaWiki\Output\OutputPage-\>output() #16 /app/bluespice/w/includes/MediaWikiEntryPoint.php(200): MediaWiki\Actions\ActionEntryPoint-\>execute() #17 /app/bluespice/w/index.php(58): MediaWiki\MediaWikiEntryPoint-\>run() #18 {main} Exception caught inside exception handler: [82b08ba2ff659d17b87ed57b] /wiki TypeError: BlueSpice\Discovery\EnhancedSidebar\Parser::\_\_construct(): Argument #1 ($revision) must be of type MediaWiki\Revision\RevisionRecord, null given, called in /app/bluespice/w/skins/BlueSpiceDiscovery/src/Component/EnhancedSidebarContainer.php on line 151 Backtrace: from /app/bluespice/w/skins/BlueSpiceDiscovery/src/EnhancedSidebar/Parser.php(53) #0 /app/bluespice/w/skins/BlueSpiceDiscovery/src/Component/EnhancedSidebarContainer.php(151): BlueSpice\Discovery\EnhancedSidebar\Parser-\>\_\_construct() #1 /app/bluespice/w/skins/BlueSpiceDiscovery/src/Component/EnhancedSidebarContainer.php(92): BlueSpice\Discovery\Component\EnhancedSidebarContainer-\>getParserData() #2 /app/bluespice/w/skins/BlueSpiceDiscovery/src/Component/EnhancedSidebarContainer.php(80): BlueSpice\Discovery\Component\EnhancedSidebarContainer-\>buildPanels() #3 /app/bluespice/w/vendor/mwstake/mediawiki-component-commonuserinterface/src/ComponentManager.php(240): BlueSpice\Discovery\Component\EnhancedSidebarContainer-\>getSubComponents() #4 /app/bluespice/w/vendor/mwstake/mediawiki-component-commonuserinterface/src/ComponentManager.php(198): MWStake\MediaWiki\Component\CommonUserInterface\ComponentManager-\>processComponent() #5 /app/bluespice/w/skins/BlueSpiceDiscovery/src/Renderer/ComponentRenderer.php(47): MWStake\MediaWiki\Component\CommonUserInterface\ComponentManager-\>getCustomComponentTree() #6 /app/bluespice/w/skins/BlueSpiceDiscovery/src/Structure/StackedTabPanelContainerBase.php(149): BlueSpice\Discovery\Renderer\ComponentRenderer-\>getComponentHtml() #7 /app/bluespice/w/skins/BlueSpiceDiscovery/src/Structure/StackedTabPanelContainerBase.php(250): BlueSpice\Discovery\Structure\StackedTabPanelContainerBase-\>buildTabPanels() #8 /app/bluespice/w/skins/BlueSpiceDiscovery/src/Renderer/SkinStructureRenderer.php(37): BlueSpice\Discovery\Structure\StackedTabPanelContainerBase-\>getParams() #9 /app/bluespice/w/skins/BlueSpiceDiscovery/src/Renderer/SkinLayoutRenderer.php(91): BlueSpice\Discovery\Renderer\SkinStructureRenderer-\>getHtml() #10 /app/bluespice/w/skins/BlueSpiceDiscovery/src/Renderer/SkinLayoutRenderer.php(55): BlueSpice\Discovery\Renderer\SkinLayoutRenderer-\>getAllStructureElementsHtml() #11 /app/bluespice/w/skins/BlueSpiceDiscovery/src/Template.php(26): BlueSpice\Discovery\Renderer\SkinLayoutRenderer-\>getHtml() #12 /app/bluespice/w/includes/skins/SkinTemplate.php(161): BlueSpice\Discovery\Template-\>execute() #13 /app/bluespice/w/includes/skins/SkinTemplate.php(180): SkinTemplate-\>generateHTML() #14 /app/bluespice/w/includes/skins/Skin.php(684): SkinTemplate-\>outputPage() #15 /app/bluespice/w/includes/Output/OutputPage.php(3193): Skin-\>outputPageFinal() #16 /app/bluespice/w/includes/exception/MWExceptionRenderer.php(190): MediaWiki\Output\OutputPage-\>output() #17 /app/bluespice/w/includes/exception/MWExceptionRenderer.php(109): MWExceptionRenderer::reportHTML() #18 /app/bluespice/w/includes/exception/MWExceptionHandler.php(135): MWExceptionRenderer::output() #19 /app/bluespice/w/includes/exception/MWExceptionHandler.php(239): MWExceptionHandler::report() #20 /app/bluespice/w/includes/MediaWikiEntryPoint.php(222): MWExceptionHandler::handleException() #21 /app/bluespice/w/includes/actions/ActionEntryPoint.php(83): MediaWiki\MediaWikiEntryPoint-\>handleTopLevelError() #22 /app/bluespice/w/includes/MediaWikiEntryPoint.php(206): MediaWiki\Actions\ActionEntryPoint-\>handleTopLevelError() #23 /app/bluespice/w/index.php(58): MediaWiki\MediaWikiEntryPoint-\>run() #24 {main} **System info:** [view system requirements](https://en.wiki.bluespice.com/wiki/Setup:System_requirements) - OS: Ubuntu Server 26.04 - Server: nginx - Database: MariaDB - BlueSpice version: 5.2.6 pro - Browser version: Chrome ---
**Author:** ![AKulbii](https://avatars.discourse-cdn.com/v4/letter/a/90db22/32.png) [@AKulbii](https://community.bluespice.com/u/AKulbii)\ **Post date:** [October 2, 2026, 10:05am UTC](https://community.bluespice.com/t/problem-after-installation-5-2-6/440/2 "2026-10-02T10:05:13Z")
Hi Lasse! Thank you for your message, and I’m very sorry for the late reply. That looks like a bug, I already created a bug ticket **50560** for that, fix will be delivered with BlueSpice **5.2.7**. If you would like to apply patch immediately, here is corresponding Gerrit change: [https://gerrit.wikimedia.org/r/c/mediawiki/skins/BlueSpiceDiscovery/+/1348523](https://gerrit.wikimedia.org/r/c/mediawiki/skins/BlueSpiceDiscovery/+/1348523) Still, I am wondering how such error could happen, I cannot reproduce it with fresh **5.2.6** build. Also, enhanced sidebar should be disabled by default. Could you please give me a bit more information about your setup? 1. Is it fresh installation or update to **5.2.6** from one of previous versions? 2. Did you probably migrate DB from somewhere? 3. Do you have some custom configuration? Greetings, Alexey.