diff --git a/CHANGELOG.md b/CHANGELOG.md
index f3243e2ae..f67b26633 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Added `FINANCIAL_MODELING_PREP` as a new data source type
 
+### Fixed
+
+- Improved the _Select all_ activities checkbox state after importing activities including a duplicate
+
+## Unreleased
+
 ### Changed
 
 - Improved the market price on the first buy date in the chart of the position detail dialog
diff --git a/apps/client/src/app/pages/portfolio/activities/import-activities-dialog/import-activities-dialog.component.ts b/apps/client/src/app/pages/portfolio/activities/import-activities-dialog/import-activities-dialog.component.ts
index 581160752..04efb7a56 100644
--- a/apps/client/src/app/pages/portfolio/activities/import-activities-dialog/import-activities-dialog.component.ts
+++ b/apps/client/src/app/pages/portfolio/activities/import-activities-dialog/import-activities-dialog.component.ts
@@ -235,8 +235,10 @@ export class ImportActivitiesDialog implements OnDestroy {
     input.click();
   }
 
-  public updateSelection(data: Activity[]) {
-    this.selectedActivities = data;
+  public updateSelection(activities: Activity[]) {
+    this.selectedActivities = activities.filter(({ isDuplicate }) => {
+      return !isDuplicate;
+    });
   }
 
   public ngOnDestroy() {
diff --git a/libs/ui/src/lib/activities-table/activities-table.component.html b/libs/ui/src/lib/activities-table/activities-table.component.html
index 45551305b..b4dc5c404 100644
--- a/libs/ui/src/lib/activities-table/activities-table.component.html
+++ b/libs/ui/src/lib/activities-table/activities-table.component.html
@@ -77,7 +77,12 @@
       <th *matHeaderCellDef class="px-1" mat-header-cell>
         <mat-checkbox
           color="primary"
-          [checked]="selectedRows.hasValue() && areAllRowsSelected()"
+          [checked]="
+            areAllRowsSelected() &&
+            !hasDuplicateActivity &&
+            selectedRows.hasValue()
+          "
+          [disabled]="hasDuplicateActivity"
           [indeterminate]="selectedRows.hasValue() && !areAllRowsSelected()"
           (change)="$event ? toggleAllRows() : null"
         ></mat-checkbox>
diff --git a/libs/ui/src/lib/activities-table/activities-table.component.ts b/libs/ui/src/lib/activities-table/activities-table.component.ts
index 0ba6e4f58..63d8811a6 100644
--- a/libs/ui/src/lib/activities-table/activities-table.component.ts
+++ b/libs/ui/src/lib/activities-table/activities-table.component.ts
@@ -66,6 +66,7 @@ export class ActivitiesTableComponent implements OnChanges, OnDestroy, OnInit {
   public endOfToday = endOfToday();
   public filters$ = new Subject<Filter[]>();
   public hasDrafts = false;
+  public hasDuplicateActivity = false;
   public isAfter = isAfter;
   public isLoading = true;
   public isUUID = isUUID;
@@ -97,6 +98,10 @@ export class ActivitiesTableComponent implements OnChanges, OnDestroy, OnInit {
           this.selectedActivities.emit(selectedRows.source.selected);
         });
     }
+
+    this.hasDuplicateActivity = this.activities.some(({ isDuplicate }) => {
+      return isDuplicate;
+    });
   }
 
   public areAllRowsSelected() {