diff --git a/src/kronecker.jl b/src/kronecker.jl
index d95b5ede9..92ece4e9e 100644
--- a/src/kronecker.jl
+++ b/src/kronecker.jl
@@ -25,6 +25,11 @@ struct IsometricKroneckerProduct{T<:Number,TB<:AbstractMatrix} <:
 end
 IsometricKroneckerProduct(ldim::Integer, B::AbstractVector) =
     IsometricKroneckerProduct(ldim, reshape(B, :, 1))
+IsometricKroneckerProduct(M::AbstractMatrix) = throw(
+    ArgumentError(
+        "Can not create IsometricKroneckerProduct from the provided matrix of type $(typeof(M))",
+    ),
+)
 
 const IKP = IsometricKroneckerProduct
 
diff --git a/src/priors/common.jl b/src/priors/common.jl
index a4cad3f70..3d4861b40 100644
--- a/src/priors/common.jl
+++ b/src/priors/common.jl
@@ -54,7 +54,7 @@ function initialize_transition_matrices(
     p::AbstractODEFilterPrior,
     dt,
 )
-    error("The chosen prior can not be implemented with a $fac factorization")
+    error("The chosen prior can not be implemented with a $FAC factorization")
 end
 
 """