diff --git a/tests/testthat.R b/tests/testthat.R
index db8aa281..eb064334 100644
--- a/tests/testthat.R
+++ b/tests/testthat.R
@@ -2,5 +2,5 @@ library(testthat)
 library(hedgehog)
 library(simstudy)
 
-
+data.table::setDTthreads(2) # added to solve CRAN issue
 test_check("simstudy")
diff --git a/vignettes/clustered.Rmd b/vignettes/clustered.Rmd
index 7e9ad7a2..144f02a8 100644
--- a/vignettes/clustered.Rmd
+++ b/vignettes/clustered.Rmd
@@ -7,6 +7,10 @@ vignette: >
   \usepackage[utf8]{inputenc}
 ---
 
+```{r chunkname, echo=-1}
+data.table::setDTthreads(2)
+```
+
 ```{r, echo = FALSE, message = FALSE}
 library(simstudy)
 library(ggplot2)
diff --git a/vignettes/corelationmat.Rmd b/vignettes/corelationmat.Rmd
index 816af704..60f2e07a 100644
--- a/vignettes/corelationmat.Rmd
+++ b/vignettes/corelationmat.Rmd
@@ -7,6 +7,9 @@ vignette: >
   \usepackage[utf8]{inputenc}
 ---
 
+```{r chunkname, echo=-1}
+data.table::setDTthreads(2)
+```
 
 ```{r, echo = FALSE, message = FALSE}
 library(simstudy)
diff --git a/vignettes/correlated.Rmd b/vignettes/correlated.Rmd
index 9fd6ffe4..5e0b48e5 100644
--- a/vignettes/correlated.Rmd
+++ b/vignettes/correlated.Rmd
@@ -7,6 +7,10 @@ vignette: >
   \usepackage[utf8]{inputenc}
 ---
 
+```{r chunkname, echo=-1}
+data.table::setDTthreads(2)
+```
+
 ```{r, echo = FALSE, message = FALSE}
 library(simstudy)
 library(ggplot2)
diff --git a/vignettes/double_dot_extension.Rmd b/vignettes/double_dot_extension.Rmd
index 0ff1b7e3..0ce7df52 100644
--- a/vignettes/double_dot_extension.Rmd
+++ b/vignettes/double_dot_extension.Rmd
@@ -7,6 +7,10 @@ vignette: >
   \usepackage[utf8]{inputenc}
 ---
 
+```{r chunkname, echo=-1}
+data.table::setDTthreads(2)
+```
+
 ```{r, echo = FALSE, message = FALSE}
 options(digits = 3)
 
diff --git a/vignettes/logisticCoefs.Rmd b/vignettes/logisticCoefs.Rmd
index 7e434eb9..7e8c843d 100644
--- a/vignettes/logisticCoefs.Rmd
+++ b/vignettes/logisticCoefs.Rmd
@@ -7,6 +7,10 @@ vignette: >
   \usepackage[utf8]{inputenc}
 ---
 
+```{r chunkname, echo=-1}
+data.table::setDTthreads(2)
+```
+
 ```{r, echo = FALSE, message = FALSE}
 library(simstudy)
 library(ggplot2)
diff --git a/vignettes/longitudinal.Rmd b/vignettes/longitudinal.Rmd
index 084c2f55..70323009 100644
--- a/vignettes/longitudinal.Rmd
+++ b/vignettes/longitudinal.Rmd
@@ -7,6 +7,10 @@ vignette: >
   \usepackage[utf8]{inputenc}
 ---
 
+```{r chunkname, echo=-1}
+data.table::setDTthreads(2)
+```
+
 ```{r, echo = FALSE, message = FALSE}
 library(simstudy)
 library(ggplot2)
diff --git a/vignettes/missing.Rmd b/vignettes/missing.Rmd
index 4aa2f74e..ce4f5d8a 100644
--- a/vignettes/missing.Rmd
+++ b/vignettes/missing.Rmd
@@ -7,6 +7,10 @@ vignette: >
   \usepackage[utf8]{inputenc}
 ---
 
+```{r chunkname, echo=-1}
+data.table::setDTthreads(2)
+```
+
 ```{r, echo = FALSE, message = FALSE}
 library(simstudy)
 library(ggplot2)
diff --git a/vignettes/ordinal.Rmd b/vignettes/ordinal.Rmd
index 162d5f67..ba365ffb 100644
--- a/vignettes/ordinal.Rmd
+++ b/vignettes/ordinal.Rmd
@@ -7,6 +7,10 @@ vignette: >
   \usepackage[utf8]{inputenc}
 ---
 
+```{r chunkname, echo=-1}
+data.table::setDTthreads(2)
+```
+
 ```{r, echo = FALSE, message = FALSE}
 library(simstudy)
 library(ggplot2)
diff --git a/vignettes/simstudy.Rmd b/vignettes/simstudy.Rmd
index 654a157d..a97541b5 100644
--- a/vignettes/simstudy.Rmd
+++ b/vignettes/simstudy.Rmd
@@ -7,6 +7,10 @@ vignette: >
   \usepackage[utf8]{inputenc}
 ---
 
+```{r chunkname, echo=-1}
+data.table::setDTthreads(2)
+```
+
 ```{r, echo = FALSE, message = FALSE}
 
 library(simstudy)
diff --git a/vignettes/spline.Rmd b/vignettes/spline.Rmd
index 5a18e338..8d07ae48 100644
--- a/vignettes/spline.Rmd
+++ b/vignettes/spline.Rmd
@@ -7,6 +7,10 @@ vignette: >
   \usepackage[utf8]{inputenc}
 ---
 
+```{r chunkname, echo=-1}
+data.table::setDTthreads(2)
+```
+
 ```{r, echo = FALSE, message = FALSE}
 library(simstudy)
 library(ggplot2)
diff --git a/vignettes/survival.Rmd b/vignettes/survival.Rmd
index c59f1b6b..25b48abb 100644
--- a/vignettes/survival.Rmd
+++ b/vignettes/survival.Rmd
@@ -7,6 +7,9 @@ vignette: >
   \usepackage[utf8]{inputenc}
 ---
 
+```{r chunkname, echo=-1}
+data.table::setDTthreads(2)
+```
 
 
 ```{r, echo = FALSE, message = FALSE}
diff --git a/vignettes/treat_and_exposure.Rmd b/vignettes/treat_and_exposure.Rmd
index 3420bf94..f19b3e07 100644
--- a/vignettes/treat_and_exposure.Rmd
+++ b/vignettes/treat_and_exposure.Rmd
@@ -7,6 +7,10 @@ vignette: >
   \usepackage[utf8]{inputenc}
 ---
 
+```{r chunkname, echo=-1}
+data.table::setDTthreads(2)
+```
+
 ```{r, echo = FALSE, message=FALSE}
 
 library(simstudy)