diff --git a/src/Interop/src/Hook.cpp b/src/Interop/src/Hook.cpp
index 4b3a036bd9..e7bcc8219a 100644
--- a/src/Interop/src/Hook.cpp
+++ b/src/Interop/src/Hook.cpp
@@ -155,7 +155,7 @@ namespace OpenLoco::Interop
         done = WriteProcessMemory(GetCurrentProcess(), (LPVOID)address, data, i, 0);
         if (!done)
         {
-            fprintf(stderr, "WriteProcessMemory failed! address = 0x%08x, size = %u, GetLastError() = 0x%08x", address, i, GetLastError());
+            fprintf(stderr, "WriteProcessMemory failed! address = 0x%08x, size = %d, GetLastError() = 0x%08x", address, i, GetLastError());
         }
 #else
         done = true;
diff --git a/src/Interop/src/Interop.cpp b/src/Interop/src/Interop.cpp
index 9c7d168401..6e9707b5a6 100644
--- a/src/Interop/src/Interop.cpp
+++ b/src/Interop/src/Interop.cpp
@@ -297,7 +297,8 @@ namespace OpenLoco::Interop
 #ifdef _WIN32
         if (!ReadProcessMemory(GetCurrentProcess(), (LPVOID)address, data, size, nullptr))
         {
-            fprintf(stderr, "ReadProcessMemory failed! address = 0x%08x, size = %u, GetLastError() = 0x%08x", address, size, GetLastError());
+            const auto errCode = static_cast<uint32_t>(GetLastError());
+            fprintf(stderr, "ReadProcessMemory failed! address = 0x%08x, size = %zu, GetLastError() = 0x%08x", address, size, errCode);
             throw std::runtime_error("ReadProcessMemory failed");
         }
 #else
@@ -311,7 +312,8 @@ namespace OpenLoco::Interop
 #ifdef _WIN32
         if (!WriteProcessMemory(GetCurrentProcess(), (LPVOID)address, data, size, nullptr))
         {
-            fprintf(stderr, "WriteProcessMemory failed! address = 0x%08x, size = %u, GetLastError() = 0x%08x", address, size, GetLastError());
+            const auto errCode = static_cast<uint32_t>(GetLastError());
+            fprintf(stderr, "WriteProcessMemory failed! address = 0x%08x, size = %zu, GetLastError() = 0x%08x", address, size, errCode);
             throw std::runtime_error("WriteProcessMemory failed");
         }
 #else