diff --git a/src/Dataloaders.jl b/src/Dataloaders.jl
index 8876ed52bb5fb8be23c0bfcb0ccae838b1352eff..2e7f50ba975ab815fbe8c4409bc65b3d1e3dacf8 100644
--- a/src/Dataloaders.jl
+++ b/src/Dataloaders.jl
@@ -767,7 +767,7 @@ end
 presample(_, ::Nothing, _, _, counts) = (0, sum(values(counts)))
 presample(_, cumulatedcount, _, _, counts) = (sum(cumulatedcount), sum(values(counts)))
 
-struct CapacitySampling <: RatioBasedSampling
+mutable struct CapacitySampling <: RatioBasedSampling
     selectors
     maxcount::Integer
     rng