diff --git a/screening/source/java/ch/systemsx/cisd/openbis/dss/etl/dto/api/v1/thumbnails/ZoomLevelBasedThumbnailsConfiguration.java b/screening/source/java/ch/systemsx/cisd/openbis/dss/etl/dto/api/v1/thumbnails/ZoomLevelBasedThumbnailsConfiguration.java
index 64657150acf9accb81515fbbc87835fca7bb62c6..8a20271c750a0d31ade0f9b012608f4ff10c33dc 100644
--- a/screening/source/java/ch/systemsx/cisd/openbis/dss/etl/dto/api/v1/thumbnails/ZoomLevelBasedThumbnailsConfiguration.java
+++ b/screening/source/java/ch/systemsx/cisd/openbis/dss/etl/dto/api/v1/thumbnails/ZoomLevelBasedThumbnailsConfiguration.java
@@ -37,7 +37,7 @@ public class ZoomLevelBasedThumbnailsConfiguration extends AbstractThumbnailsCon
         thumbnailsStorageFormat.setAllowedMachineLoadDuringGeneration(config
                 .getAllowedMachineLoadDuringThumbnailsGeneration());
         thumbnailsStorageFormat.setZoomLevel(zoomLevel);
-        thumbnailsStorageFormat.setThumbnailsFileName(String.format("thumbnails_%.0f%%.h5",
+        thumbnailsStorageFormat.setThumbnailsFileName(String.format("thumbnails_%.0fpct.h5",
                 zoomLevel * 100.0));
         thumbnailsStorageFormat.setGenerateWithImageMagic(config
                 .getGenerateThumbnailsWithImageMagic());