diff --git a/lib/layouts/memoir.layout b/lib/layouts/memoir.layout
index 7c1bc9e930..63abd2cd5e 100644
--- a/lib/layouts/memoir.layout
+++ b/lib/layouts/memoir.layout
@@ -13,6 +13,7 @@ SecNumDepth        2
 TocDepth           2
 DefaultStyle       Standard
 PageStyle          Headings
+ProvidesMakeidx    1
 
 
 ClassOptions
diff --git a/src/LaTeX.C b/src/LaTeX.C
index 90092a7cf9..5837c5d9b3 100644
--- a/src/LaTeX.C
+++ b/src/LaTeX.C
@@ -269,6 +269,11 @@ int LaTeX::run(TeXErrors & terr)
 	// the .aux file is checked for signs of bibtex. Bibtex is then run
 	// if needed.
 
+	// memoir (at least) writes an empty *idx file in the first place.
+	// A second latex run is needed.
+	rerun = fs::exists(ChangeExtension(file, ".idx"))
+		&& fs::is_empty(ChangeExtension(file, ".idx"));
+
 	// run makeindex
 	if (head.haschanged(onlyFilename(changeExtension(file, ".idx")))) {
 		// no checks for now
@@ -331,7 +336,7 @@ int LaTeX::run(TeXErrors & terr)
 
 	// 1.5
 	// The inclusion of files generated by external programs like
-	// makeindex or bibtex might have done changes to pagenumbereing,
+	// makeindex or bibtex might have done changes to pagenumbering,
 	// etc. And because of this we must run the external programs
 	// again to make sure everything is redone correctly.
 	// Also there should be no need to run the external programs any
diff --git a/src/LaTeXFeatures.C b/src/LaTeXFeatures.C
index 347c10a814..2a2b757436 100644
--- a/src/LaTeXFeatures.C
+++ b/src/LaTeXFeatures.C
@@ -294,7 +294,7 @@ string const LaTeXFeatures::getPackages() const
 
 	// makeidx.sty
 	if (isRequired("makeidx")) {
-		if (! tclass.provides(LyXTextClass::makeidx))
+		if (!tclass.provides(LyXTextClass::makeidx))
 			packages << "\\usepackage{makeidx}\n";
 		packages << "\\makeindex\n";
 	}