diff --git a/dlls/riched20/richole.c b/dlls/riched20/richole.c
index 008c1241b0e..5b0c7fc6898 100644
--- a/dlls/riched20/richole.c
+++ b/dlls/riched20/richole.c
@@ -2445,6 +2445,9 @@ static HRESULT WINAPI TextFont_Reset(ITextFont *iface, LONG value)
             This->set_cache_enabled = FALSE;
             textfont_apply_range_props(This);
             break;
+        case tomUsePoints:
+        case tomUseTwips:
+            return E_INVALIDARG;
         default:
             FIXME("reset mode %d not supported\n", value);
         }
@@ -2467,6 +2470,9 @@ static HRESULT WINAPI TextFont_Reset(ITextFont *iface, LONG value)
         case tomTrackParms:
         case tomCacheParms:
             return S_OK;
+        case tomUsePoints:
+        case tomUseTwips:
+            return E_INVALIDARG;
         }
     }
 
diff --git a/dlls/riched20/tests/richole.c b/dlls/riched20/tests/richole.c
index 327b3acf7f1..f2ad6e2b2c0 100644
--- a/dlls/riched20/tests/richole.c
+++ b/dlls/riched20/tests/richole.c
@@ -2141,6 +2141,12 @@ static void test_ITextFont(void)
   hr = ITextRange_GetFont(range, &font);
   ok(hr == S_OK, "got 0x%08x\n", hr);
 
+  hr = ITextFont_Reset(font, tomUseTwips);
+  ok(hr == E_INVALIDARG, "got 0x%08x\n", hr);
+
+  hr = ITextFont_Reset(font, tomUsePoints);
+  ok(hr == E_INVALIDARG, "got 0x%08x\n", hr);
+
   hr = ITextFont_GetName(font, NULL);
   ok(hr == E_INVALIDARG, "got 0x%08x\n", hr);
 
@@ -2176,6 +2182,23 @@ static void test_ITextFont(void)
   ok(position == twips_to_points(cf.yOffset), "got yOffset %d, position %.2f\n", cf.yOffset, position);
   ok(kerning == twips_to_points(cf.wKerning), "got wKerning %d, kerning %.2f\n", cf.wKerning, kerning);
 
+  hr = ITextFont_Reset(font, tomUseTwips);
+  ok(hr == E_INVALIDARG, "got 0x%08x\n", hr);
+
+  hr = ITextFont_Reset(font, tomUsePoints);
+  ok(hr == E_INVALIDARG, "got 0x%08x\n", hr);
+
+  hr = ITextFont_GetDuplicate(font, &font2);
+  ok(hr == S_OK, "got 0x%08x\n", hr);
+
+  hr = ITextFont_Reset(font2, tomUseTwips);
+  ok(hr == E_INVALIDARG, "got 0x%08x\n", hr);
+
+  hr = ITextFont_Reset(font2, tomUsePoints);
+  ok(hr == E_INVALIDARG, "got 0x%08x\n", hr);
+
+  ITextFont_Release(font2);
+
   /* default font name */
   str = NULL;
   hr = ITextFont_GetName(font, &str);