diff --git a/ci/ci_verify_cmake.sh b/ci/ci_verify_cmake.sh
index 1d3e9734e..908b90ad5 100755
--- a/ci/ci_verify_cmake.sh
+++ b/ci/ci_verify_cmake.sh
@@ -82,13 +82,12 @@ function ci_trace_build {
 }
 
 function ci_cleanup_old_build {
-    if [[ -e $CI_BUILD_DIR || -e $CI_INSTALL_DIR ]]
-    then
-        ci_info "## START OF PRE-BUILD CLEANUP ##"
+    ci_info "## START OF PRE-BUILD CLEANUP ##"
+    [[ ! -e $CI_BUILD_DIR && ! -e $CI_INSTALL_DIR ]] || {
         ci_spawn rm -fr "$CI_BUILD_DIR"
         ci_spawn rm -fr "$CI_INSTALL_DIR"
-        ci_info "## END OF PRE-BUILD CLEANUP ##"
-    fi
+    }
+    ci_info "## END OF PRE-BUILD CLEANUP ##"
 }
 
 function ci_build {
@@ -127,7 +126,7 @@ function ci_build {
         ci_spawn export CMAKE_GENERATOR="$CI_CMAKE_GENERATOR"
     [[ $CI_CMAKE_GENERATOR_PLATFORM ]] &&
         ci_spawn export CMAKE_GENERATOR_PLATFORM="$CI_CMAKE_GENERATOR_PLATFORM"
-    # Build!
+    # And... build!
     # Use $CI_BUILD_TO_SRC_RELDIR and $CI_BUILD_TO_INSTALL_RELDIR
     # instead of $CI_SRC_DIR and $CI_INSTALL_DIR from this point onwards.
     ci_spawn mkdir -p "$CI_BUILD_DIR"
@@ -181,6 +180,7 @@ function main {
         ci_err "unknown option: '$1'"
     done
     shift $((OPTIND - 1))
+    # And... go!
     ci_init_build
     ci_trace_build
     [[ $# -eq 0 ]] || {
diff --git a/ci/ci_verify_configure.sh b/ci/ci_verify_configure.sh
index 9be76d986..4542070e1 100755
--- a/ci/ci_verify_configure.sh
+++ b/ci/ci_verify_configure.sh
@@ -73,13 +73,19 @@ function ci_trace_build {
 }
 
 function ci_cleanup_old_build {
-    if [[ -e $CI_BUILD_DIR || -e $CI_INSTALL_DIR ]]
-    then
-        ci_info "## START OF PRE-BUILD CLEANUP ##"
+    ci_info "## START OF PRE-BUILD CHECKUP ##"
+    ci_spawn test '!' -f "$CI_SRC_DIR/config.status" || {
+        # Warn the user, but do not delete their files.
+        ci_warn "unexpected build configuration file: '$CI_SRC_DIR/config.status'"
+        ci_warn "the configure script might fail"
+    }
+    ci_info "## END OF PRE-BUILD CHECKUP ##"
+    ci_info "## START OF PRE-BUILD CLEANUP ##"
+    [[ ! -e $CI_BUILD_DIR && ! -e $CI_INSTALL_DIR ]] || {
         ci_spawn rm -fr "$CI_BUILD_DIR"
         ci_spawn rm -fr "$CI_INSTALL_DIR"
-        ci_info "## END OF PRE-BUILD CLEANUP ##"
-    fi
+    }
+    ci_info "## END OF PRE-BUILD CLEANUP ##"
 }
 
 function ci_build {
@@ -97,7 +103,7 @@ function ci_build {
         ci_spawn export CFLAGS="-fsanitize=$CI_SANITIZERS ${CFLAGS:-"-O2"}"
         ci_spawn export LDFLAGS="-fsanitize=$CI_SANITIZERS $LDFLAGS"
     }
-    # Build!
+    # And... build!
     ci_spawn mkdir -p "$CI_BUILD_DIR"
     ci_spawn cd "$CI_BUILD_DIR"
     # Spawn "configure".
diff --git a/ci/ci_verify_makefiles.sh b/ci/ci_verify_makefiles.sh
index beda3b470..511a72b34 100755
--- a/ci/ci_verify_makefiles.sh
+++ b/ci/ci_verify_makefiles.sh
@@ -108,7 +108,7 @@ function ci_build {
     [[ $ALL_LD_FLAGS ]] && ALL_MAKE_VARS+=(LDFLAGS="$ALL_LD_FLAGS")
     [[ $CI_LIBS ]] && ALL_MAKE_VARS+=(LIBS="$CI_LIBS")
     ALL_MAKE_VARS+=($CI_MAKE_VARS)
-    # Build!
+    # And... build!
     local MY_MAKEFILE
     for MY_MAKEFILE in $CI_MAKEFILES
     do