diff --git a/3rdparty/3rdparty.pro b/3rdparty/3rdparty.pro
index 327ceb2..dac92ce 100644
--- a/3rdparty/3rdparty.pro
+++ b/3rdparty/3rdparty.pro
@@ -1,3 +1,3 @@
 TEMPLATE = subdirs
 
-SUBDIRS += Quazip
+exists(Quazip/Quazip.pro): SUBDIRS += Quazip
diff --git a/DbSoftware.pro b/DbSoftware.pro
index e6cead7..e1f7d9f 100644
--- a/DbSoftware.pro
+++ b/DbSoftware.pro
@@ -1,31 +1,32 @@
 TEMPLATE = subdirs
 
-SUBDIRS += 3rdparty \
-           DbDatabaseTree \
-           DbHashCracker \
-           DbMessaging \
-           DbNeuralNet \
-           DbPathFinder \
-           DbPicSync \
-           DbRadioDumper
-qtHaveModule(serialport): SUBDIRS += DbSerialServer
-else: message("serialport is missing, will not build DbSerialServer")
-SUBDIRS += DbSketch \
-           DbTernaryClock \
-           DbTictactoe \
-           DbWebserver \
-           DbZeiterfassung \
-           libs
+SUBDIRS += 3rdparty libs
+exists(DbDatabaseTree/DbDatabaseTree.pro): SUBDIRS += DbDatabaseTree
+exists(DbHashCracker/DbHashCracker.pro): SUBDIRS += DbHashCracker
+exists(DbMessaging/DbMessaging.pro): SUBDIRS += DbMessaging
+exists(DbNeuralNet/DbNeuralNet.pro): SUBDIRS += DbNeuralNet
+exists(DbPathFinder/DbPathFinder.pro): SUBDIRS += DbPathFinder
+exists(DbPicSync/DbPicSync.pro): SUBDIRS += DbPicSync
+exists(DbRadioDumper/DbRadioDumper.pro): SUBDIRS += DbRadioDumper
+exists(DbSerialServer/DbSerialServer.pro): {
+    qtHaveModule(serialport): SUBDIRS += DbSerialServer
+    else: message("serialport is missing, will not build DbSerialServer")
+}
+exists(DbSketch/DbSketch.pro): SUBDIRS += DbSketch
+exists(DbTernaryClock/DbTernaryClock.pro): SUBDIRS += DbTernaryClock
+exists(DbTictactoe/DbTictactoe.pro): SUBDIRS += DbTictactoe
+exists(DbWebserver/DbWebserver.pro): SUBDIRS += DbWebserver
+exists(DbZeiterfassung/DbZeiterfassung.pro): SUBDIRS += DbZeiterfassung
+
+contains(SUBDIRS, DbSerialServer): DbSerialServer.depends += libs
+contains(SUBDIRS, DbSketch): DbSketch.depends += 3rdparty
+contains(SUBDIRS, DbTernaryClock): DbTernaryClock.depends += libs
+contains(SUBDIRS, DbWebserver): DbWebserver.depends += libs
+contains(SUBDIRS, DbZeiterfassung): DbZeiterfassung.depends += 3rdparty DbSketch libs
 
 OTHER_FILES += app.pri \
                lib.pri \
                project.pri
 
-contains(SUBDIRS, DbSerialServer): DbSerialServer.depends += libs
-DbSketch.depends += 3rdparty
-DbTernaryClock.depends += libs
-DbWebserver.depends += libs
-DbZeiterfassung.depends += 3rdparty DbSketch libs
-
 include(installs.pri)
 win32: include(installs_win32.pri)
diff --git a/DbWebserver b/DbWebserver
index c611917..ecb30b5 160000
--- a/DbWebserver
+++ b/DbWebserver
@@ -1 +1 @@
-Subproject commit c611917d9aa989d42c60820ced7d251b1a2879a4
+Subproject commit ecb30b5fd640c085ba1cb386a9541e28f8cbffa6
diff --git a/DbZeiterfassung b/DbZeiterfassung
index 29db99a..39fdeed 160000
--- a/DbZeiterfassung
+++ b/DbZeiterfassung
@@ -1 +1 @@
-Subproject commit 29db99a9182cd5067605583bbd0adef39febbfdc
+Subproject commit 39fdeed141598d9365f5f2a42baf3639d60bdc0b
diff --git a/libs/libs.pro b/libs/libs.pro
index c280450..6b91ae7 100644
--- a/libs/libs.pro
+++ b/libs/libs.pro
@@ -1,8 +1,9 @@
 TEMPLATE = subdirs
 
-SUBDIRS += DbCoreLib \
-           DbGuiLib \
-           DbNetworkLib \
-           unittests
+exists(DbCoreLib/DbCoreLib.pro): SUBDIRS += DbCoreLib
+exists(DbGuiLib/DbGuiLib.pro): SUBDIRS += DbGuiLib
+exists(DbNetworkLib/DbNetworkLib.pro): SUBDIRS += DbNetworkLib
+
+SUBDIRS += unittests
 
 unittests.depends += DbCoreLib
diff --git a/libs/unittests/unittests.pro b/libs/unittests/unittests.pro
index 720a88d..b8ac197 100644
--- a/libs/unittests/unittests.pro
+++ b/libs/unittests/unittests.pro
@@ -1,3 +1,3 @@
 TEMPLATE = subdirs
 
-SUBDIRS += TstFixedSizeMatrix
+exists(TstFixedSizeMatrix/TstFixedSizeMatrix.pro): SUBDIRS += TstFixedSizeMatrix