NullPointerException when trying to load map

[BasketBandit]

Hi, trying to build the map. When I run the docker container, it downloads the cache (2025-07-18_15_15_23) seemingly without issue but once extracted it appears that main_file_cache.idx19 (which after debugging is I think where map data is stored) is empty (0KB) and is causing this null pointer exception. (see below)

Perhaps I'm doing something wrong?

2025-07-19 21:04:14 INFO Building map base images
[main] INFO net.runelite.cache.util.XteaKeyManager - Loaded 2237 keys
Exception in thread "main" java.lang.NullPointerException
at net.runelite.cache.fs.Storage.loadArchive(Storage.java:46)
at net.runelite.cache.WorldMapManager.load(WorldMapManager.java:66)
at net.runelite.cache.MapImageDumper.load(MapImageDumper.java:231)
at org.explv.mapimage.Main.main(Main.java:91)

[BasketBandit]

Digging deeper, perhaps this is just a partial cache?

EDIT: I downloaded an older cache which contained idx19 and its working now!