diff --git a/src/vs/workbench/contrib/extensions/browser/fileBasedRecommendations.ts b/src/vs/workbench/contrib/extensions/browser/fileBasedRecommendations.ts
index 0de614759e0fce5d3df8c61da8179dcca83f2203..29e92583235c98da738e9b49412b3839f093bfdc 100644
--- a/src/vs/workbench/contrib/extensions/browser/fileBasedRecommendations.ts
+++ b/src/vs/workbench/contrib/extensions/browser/fileBasedRecommendations.ts
@@ -26,6 +26,7 @@ import { IModelService } from 'vs/editor/common/services/modelService';
 import { setImmediate } from 'vs/base/common/platform';
 import { IModeService } from 'vs/editor/common/services/modeService';
 import { IExtensionRecommendationNotificationService, RecommendationsNotificationResult, RecommendationSource } from 'vs/platform/extensionRecommendations/common/extensionRecommendations';
+import { distinct } from 'vs/base/common/arrays';
 
 type FileExtensionSuggestionClassification = {
 	userReaction: { classification: 'SystemMetaData', purpose: 'FeatureInsight' };
@@ -33,6 +34,7 @@ type FileExtensionSuggestionClassification = {
 };
 
 const promptedRecommendationsStorageKey = 'fileBasedRecommendations/promptedRecommendations';
+const promptedFileExtensionsStorageKey = 'fileBasedRecommendations/promptedFileExtensions';
 const recommendationsStorageKey = 'extensionsAssistant/recommendations';
 const searchMarketplace = localize('searchMarketplace', "Search Marketplace");
 const milliSecondsInADay = 1000 * 60 * 60 * 24;
@@ -164,7 +166,7 @@ export class FileBasedRecommendations extends ExtensionRecommendations {
 		}
 
 		const language = model.getLanguageIdentifier().language;
-		const fileExtension = extname(uri);
+		const fileExtension = extname(uri).toLowerCase();
 		if (this.processedLanguages.includes(language) && this.processedFileExtensions.includes(fileExtension)) {
 			return;
 		}
@@ -272,12 +274,27 @@ export class FileBasedRecommendations extends ExtensionRecommendations {
 		this.storageService.store(promptedRecommendationsStorageKey, JSON.stringify(promptedRecommendations), StorageScope.GLOBAL);
 	}
 
+	private getPromptedFileExtensions(): string[] {
+		return JSON.parse(this.storageService.get(promptedFileExtensionsStorageKey, StorageScope.GLOBAL, '[]'));
+	}
+
+	private addToPromptedFileExtensions(fileExtension: string) {
+		const promptedFileExtensions = this.getPromptedFileExtensions();
+		promptedFileExtensions.push(fileExtension);
+		this.storageService.store(promptedFileExtensionsStorageKey, JSON.stringify(distinct(promptedFileExtensions)), StorageScope.GLOBAL);
+	}
+
 	private async promptRecommendedExtensionForFileExtension(fileExtension: string, installed: IExtension[]): Promise<void> {
 		const fileExtensionSuggestionIgnoreList = <string[]>JSON.parse(this.storageService.get('extensionsAssistant/fileExtensionsSuggestionIgnore', StorageScope.GLOBAL, '[]'));
 		if (fileExtensionSuggestionIgnoreList.indexOf(fileExtension) > -1) {
 			return;
 		}
 
+		const promptedFileExtensions = this.getPromptedFileExtensions();
+		if (promptedFileExtensions.includes(fileExtension)) {
+			return;
+		}
+
 		const text = `ext:${fileExtension}`;
 		const pager = await this.extensionsWorkbenchService.queryGallery({ text, pageSize: 100 }, CancellationToken.None);
 		if (pager.firstPage.length === 0) {
@@ -295,6 +312,7 @@ export class FileBasedRecommendations extends ExtensionRecommendations {
 			[{
 				label: searchMarketplace,
 				run: () => {
+					this.addToPromptedFileExtensions(fileExtension);
 					this.telemetryService.publicLog2<{ userReaction: string, fileExtension: string }, FileExtensionSuggestionClassification>('fileExtensionSuggestion:popup', { userReaction: 'ok', fileExtension });
 					this.viewletService.openViewlet('workbench.view.extensions', true)
 						.then(viewlet => viewlet?.getViewPaneContainer() as IExtensionsViewPaneContainer)