diff --git a/include/llfio/v2.0/detail/impl/windows/file_handle.ipp b/include/llfio/v2.0/detail/impl/windows/file_handle.ipp
index d3417b61a..721641a49 100644
--- a/include/llfio/v2.0/detail/impl/windows/file_handle.ipp
+++ b/include/llfio/v2.0/detail/impl/windows/file_handle.ipp
@@ -718,7 +718,7 @@ result<file_handle::extent_pair> file_handle::clone_extents_to(file_handle::exte
             buffer = utils::page_allocator<byte>().allocate(blocksize);
           }
           deadline nd;
-          buffer_type b(buffer, utils::round_up_to_page_size(thisblock, 4096) /* to allow aligned i/o files */);
+          buffer_type b(buffer, utils::round_up_to_page_size((size_t) thisblock, 4096) /* to allow aligned i/o files */);
           LLFIO_DEADLINE_TO_PARTIAL_DEADLINE(nd, d);
           OUTCOME_TRY(auto &&readed, read({{&b, 1}, item.src.offset + thisoffset}, nd));
           buffer_dirty = true;
@@ -726,9 +726,9 @@ result<file_handle::extent_pair> file_handle::clone_extents_to(file_handle::exte
           {
             return errc::resource_unavailable_try_again;  // something is wrong
           }
-          readed.front() = {readed.front().data(), thisblock};
+          readed.front() = {readed.front().data(), (size_t) thisblock};
           LLFIO_DEADLINE_TO_PARTIAL_DEADLINE(nd, d);
-          const_buffer_type cb(readed.front().data(), thisblock);
+          const_buffer_type cb(readed.front().data(), (size_t) thisblock);
           if(item.destination_extents_are_new)
           {
             // If we don't need to reset the bytes in the destination, try to elide
diff --git a/include/llfio/v2.0/detail/impl/windows/map_handle.ipp b/include/llfio/v2.0/detail/impl/windows/map_handle.ipp
index b10539c32..3a8dd9051 100644
--- a/include/llfio/v2.0/detail/impl/windows/map_handle.ipp
+++ b/include/llfio/v2.0/detail/impl/windows/map_handle.ipp
@@ -693,7 +693,7 @@ result<map_handle> map_handle::map(section_handle &section, size_type bytes, ext
   }
   if(bytes == 0u)
   {
-    bytes = length;
+    bytes = (size_type) length;
   }
   else if(length > bytes)
   {
@@ -718,7 +718,7 @@ result<map_handle> map_handle::map(section_handle &section, size_type bytes, ext
   ret.value()._addr = static_cast<byte *>(addr);
   ret.value()._offset = offset;
   ret.value()._reservation = _bytes - (offset & 65535);
-  ret.value()._length = length;
+  ret.value()._length = (size_type) length;
   ret.value()._pagesize = pagesize;
   // Make my handle borrow the native handle of my backing storage
   ret.value()._v.h = section.backing_native_handle().h;
@@ -800,7 +800,7 @@ result<map_handle::size_type> map_handle::truncate(size_type newsize, bool /* un
     // If newsize isn't exactly a previous extension, this will fail, same as for the VirtualAlloc case
     OUTCOME_TRY(win32_release_file_allocations(_addr + newsize, _reservation - newsize));
     _reservation = newsize;
-    _length = length;
+    _length = (size_type) length;
     return _reservation;
   }
   // Try to map an additional part of the section directly after this map
@@ -818,7 +818,7 @@ result<map_handle::size_type> map_handle::truncate(size_type newsize, bool /* un
     return ntkernel_error(ntstat);
   }
   _reservation += _bytes;
-  _length = length;
+  _length = (size_type) length;
   return _reservation;
 }