diff --git a/lib/base/CMakeLists.txt b/lib/base/CMakeLists.txt
index f4bdec383..d19496f09 100644
--- a/lib/base/CMakeLists.txt
+++ b/lib/base/CMakeLists.txt
@@ -4,6 +4,7 @@ target_sources(trbase
     PRIVATE
         env.cc
         env.h
+        error-types.h
         error.cc
         error.h
         file-posix.cc
diff --git a/libtransmission/error-types.h b/lib/base/error-types.h
similarity index 100%
rename from libtransmission/error-types.h
rename to lib/base/error-types.h
diff --git a/lib/base/file-utils.cc b/lib/base/file-utils.cc
index 5d1715180..5182232db 100644
--- a/lib/base/file-utils.cc
+++ b/lib/base/file-utils.cc
@@ -12,12 +12,12 @@
 
 #include <fmt/format.h>
 
+#include "lib/base/error-types.h"
 #include "lib/base/error.h"
-#include "lib/base/file.h"
 #include "lib/base/file-utils.h"
+#include "lib/base/file.h"
 #include "lib/base/tr-strbuf.h"
 
-#include "libtransmission/error-types.h"
 #include "libtransmission/log.h"
 #include "libtransmission/utils.h"
 
diff --git a/libtransmission/CMakeLists.txt b/libtransmission/CMakeLists.txt
index 8d5fbd54e..9dd673fd3 100644
--- a/libtransmission/CMakeLists.txt
+++ b/libtransmission/CMakeLists.txt
@@ -53,7 +53,6 @@ target_sources(${TR_NAME}
         crypto-utils-wolfssl.cc
         crypto-utils.cc
         crypto-utils.h
-        error-types.h
         file-piece-map.cc
         file-piece-map.h
         handshake.cc
@@ -267,7 +266,6 @@ if(INSTALL_LIB)
         DESTINATION ${CMAKE_INSTALL_LIBDIR})
     install(
         FILES
-            error-types.h
             ../lib/base/file.h
             log.h
             makemeta.h
diff --git a/libtransmission/magnet-metainfo.cc b/libtransmission/magnet-metainfo.cc
index 41f105622..1564bf69b 100644
--- a/libtransmission/magnet-metainfo.cc
+++ b/libtransmission/magnet-metainfo.cc
@@ -15,11 +15,11 @@
 
 #include <fmt/format.h>
 
+#include "lib/base/error-types.h"
 #include "lib/base/error.h"
 #include "lib/base/tr-strbuf.h" // for tr_urlbuf
 
 #include "libtransmission/crypto-utils.h"
-#include "libtransmission/error-types.h"
 #include "libtransmission/magnet-metainfo.h"
 #include "lib/base/string-utils.h"
 #include "libtransmission/types.h" // for tr_sha1_digest_t
diff --git a/libtransmission/open-files.cc b/libtransmission/open-files.cc
index dd62ef80b..6d20b92e1 100644
--- a/libtransmission/open-files.cc
+++ b/libtransmission/open-files.cc
@@ -11,12 +11,12 @@
 
 #include <fmt/format.h>
 
+#include "lib/base/error-types.h"
 #include "lib/base/error.h"
 #include "lib/base/file.h"
 #include "lib/base/tr-assert.h"
 #include "lib/base/tr-strbuf.h"
 
-#include "libtransmission/error-types.h"
 #include "libtransmission/log.h"
 #include "libtransmission/open-files.h"
 #include "libtransmission/types.h"
diff --git a/libtransmission/session-id.cc b/libtransmission/session-id.cc
index 98017a847..c43ddbff0 100644
--- a/libtransmission/session-id.cc
+++ b/libtransmission/session-id.cc
@@ -13,12 +13,12 @@
 
 #include <fmt/format.h>
 
+#include "lib/base/error-types.h"
 #include "lib/base/error.h"
 #include "lib/base/file.h"
 #include "lib/base/tr-strbuf.h" // for tr_pathbuf
 
 #include "libtransmission/crypto-utils.h" // for tr_rand_obj()
-#include "libtransmission/error-types.h"
 #include "libtransmission/log.h"
 #include "libtransmission/platform.h"
 #include "libtransmission/session-id.h"
diff --git a/libtransmission/watchdir.cc b/libtransmission/watchdir.cc
index 52abd12da..cc8436711 100644
--- a/libtransmission/watchdir.cc
+++ b/libtransmission/watchdir.cc
@@ -9,12 +9,12 @@
 
 #include <fmt/format.h>
 
+#include "lib/base/error-types.h"
 #include "lib/base/error.h"
 #include "lib/base/file.h"
 #include "lib/base/tr-strbuf.h"
 
 #define LIBTRANSMISSION_WATCHDIR_MODULE
-#include "libtransmission/error-types.h"
 #include "libtransmission/log.h"
 #include "libtransmission/utils.h" // for _()
 #include "libtransmission/watchdir-base.h"