diff --git a/src/general/buffer.jl b/src/general/buffer.jl
index b12cf05f3..aae5ccb5c 100644
--- a/src/general/buffer.jl
+++ b/src/general/buffer.jl
@@ -1,10 +1,11 @@
 struct SystemBuffer{V}
-    active_particle :: BitVector
+    active_particle :: Vector{Bool}
     eachparticle    :: V # Vector{Int}
     buffer_size     :: Int
 
     function SystemBuffer(active_size, buffer_size::Integer)
-        active_particle = vcat(trues(active_size), falses(buffer_size))
+        # We cannot use a `BitVector` here, as writing to a `BitVector` is not thread-safe
+        active_particle = vcat(fill(true, active_size), fill(false, buffer_size))
         eachparticle = collect(1:active_size)
 
         return new{typeof(eachparticle)}(active_particle, eachparticle, buffer_size)
diff --git a/src/preprocessing/geometries/triangle_mesh.jl b/src/preprocessing/geometries/triangle_mesh.jl
index e8cc993af..60d850e81 100644
--- a/src/preprocessing/geometries/triangle_mesh.jl
+++ b/src/preprocessing/geometries/triangle_mesh.jl
@@ -194,7 +194,8 @@ function unique_sorted(vertices)
     # Sort by the first entry of the vectors
     compare_first_element = (x, y) -> x[1] < y[1]
     vertices_sorted = sort!(vertices, lt=compare_first_element)
-    keep = trues(length(vertices_sorted))
+    # We cannot use a `BitVector` here, as writing to a `BitVector` is not thread-safe
+    keep = fill(true, length(vertices_sorted))
 
     PointNeighbors.@threaded vertices_sorted for i in eachindex(vertices_sorted)
         # We only sorted by the first entry, so we have to check all previous vertices
diff --git a/src/schemes/boundary/open_boundary/boundary_zones.jl b/src/schemes/boundary/open_boundary/boundary_zones.jl
index 586d565b1..d8ec0a051 100644
--- a/src/schemes/boundary/open_boundary/boundary_zones.jl
+++ b/src/schemes/boundary/open_boundary/boundary_zones.jl
@@ -326,7 +326,7 @@ end
 function remove_outside_particles(initial_condition, spanning_set, zone_origin)
     (; coordinates, density, particle_spacing) = initial_condition
 
-    in_zone = trues(nparticles(initial_condition))
+    in_zone = fill(true, nparticles(initial_condition))
 
     for particle in eachparticle(initial_condition)
         current_position = current_coords(coordinates, initial_condition, particle)