diff --git a/make/projects-dir.mk b/make/projects-dir.mk
index c3d2fe02..40f01772 100644
--- a/make/projects-dir.mk
+++ b/make/projects-dir.mk
@@ -68,10 +68,9 @@ ifeq ($(JANWARE_USER),)
   UNAVAILABLE_TARGETS ?= pull.done update.done clone.done
 else
   UNAVAILABLE_TARGETS ?=
+  export CVSROOT = :ext:$(JANWARE_USER)@cvs.jannet.de:/home/jannet/arc/cvs
 endif
 
-export CVSROOT = :ext:$(JANWARE_USER)@cvs.jannet.de:/home/jannet/arc/cvs
-
 ifneq ($(JW_BUILD_SSH),)
   export CVS_RSH := $(JW_BUILD_SSH)
 else
@@ -300,16 +299,22 @@ clean.ssh-wrapper:
 	rm -f $(SSH_WRAPPER_SH)
 clean: clean.ssh-wrapper
 
+cvs-check-user:
+	@if ! grep -q ":ext:$(JANWARE_USER)@" CVS/Root; then \
+		echo "Wrong username in CVS/Root, change that to: $(CVSROOT)" ;\
+		exit 1; \
+	fi
+
 cvsdir.done: $(SSH_WRAPPER_SH)
 	if [ ! -d CVS ]; then \
 		mkdir CVS && \
-		echo :ext:$(JANWARE_USER)@cvs.jannet.de:/home/jannet/arc/cvs > CVS/Root && \
+		echo $(CVSROOT) > CVS/Root && \
 		echo proj > CVS/Repository && \
 		echo "/Makefile/$Revision$ ///" | sed 's/ *evision: *\([0-9.]*\) */\1/; s/ *$$ *//' > CVS/Entries ;\
 	fi
 	touch $@
 
-cvs-update.done: $(filter-out $(UNAVAILABLE_TARGETS),cvsdir.done $(SSH_WRAPPER_SH))
+cvs-update.done: cvsdir.done $(SSH_WRAPPER_SH) cvs-check-user
 	cvs update -dP Makefile $(shell $(CVS_ADMIN_SH) list-projects)
 	touch $@