diff --git a/regtest/logmfd/rt-logmfd-nve/config b/regtest/logmfd/rt-logmfd-nve/config
index fb67c7e879..2c1d496468 100644
--- a/regtest/logmfd/rt-logmfd-nve/config
+++ b/regtest/logmfd/rt-logmfd-nve/config
@@ -2,5 +2,6 @@ type=simplemd
 plumed_modules=logmfd
 arg="--plumed plumed.dat < in"
 extra_files="../input.xyz"
+export PLUMED_NUM_THREADS=1
 
 
diff --git a/regtest/logmfd/rt-logmfd-nvt/config b/regtest/logmfd/rt-logmfd-nvt/config
index fb67c7e879..77faf5d9ce 100644
--- a/regtest/logmfd/rt-logmfd-nvt/config
+++ b/regtest/logmfd/rt-logmfd-nvt/config
@@ -2,5 +2,5 @@ type=simplemd
 plumed_modules=logmfd
 arg="--plumed plumed.dat < in"
 extra_files="../input.xyz"
-
+export PLUMED_NUM_THREADS=1
 
diff --git a/regtest/logmfd/rt-logmfd-vs/config b/regtest/logmfd/rt-logmfd-vs/config
index fb67c7e879..2c1d496468 100644
--- a/regtest/logmfd/rt-logmfd-vs/config
+++ b/regtest/logmfd/rt-logmfd-vs/config
@@ -2,5 +2,6 @@ type=simplemd
 plumed_modules=logmfd
 arg="--plumed plumed.dat < in"
 extra_files="../input.xyz"
+export PLUMED_NUM_THREADS=1