diff --git a/DESCRIPTION b/DESCRIPTION
index c95147789..d00656a84 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -1,7 +1,7 @@
 Package: tinytex
 Type: Package
 Title: Helper Functions to Install and Maintain TeX Live, and Compile LaTeX Documents
-Version: 0.47.2
+Version: 0.47.3
 Authors@R: c(
   person("Yihui", "Xie", role = c("aut", "cre", "cph"), email = "xie@yihui.name", comment = c(ORCID = "0000-0003-0645-5666")),
   person(given = "Posit Software, PBC", role = c("cph", "fnd")),
diff --git a/R/latex.R b/R/latex.R
index da37a8015..d2f667fee 100644
--- a/R/latex.R
+++ b/R/latex.R
@@ -298,7 +298,7 @@ tweak_aux = function(aux, x = read_lines(aux)) {
   writeLines(x, aux)
 }
 
-needs_rerun = function(log, text = xfun::read_utf8(log)) {
+needs_rerun = function(log, text = read_lines(log)) {
   any(grepl(
     '(Rerun to get |Please \\(?re\\)?run | Rerun LaTeX\\.)', text,
     useBytes = TRUE
@@ -314,7 +314,7 @@ system2_quiet = function(..., error = NULL, logfile = NULL, fail_rerun = TRUE) {
 
   # run the command quietly if possible
   res = system2(..., stdout = if (use_file_stdout()) f1 else FALSE, stderr = f2)
-  if (is.character(logfile) && file.exists(f2) && length(e <- xfun::read_utf8(f2))) {
+  if (is.character(logfile) && file.exists(f2) && length(e <- read_lines(f2))) {
     i = grep('^\\s*$', e, invert = TRUE)
     e[i] = paste('!', e[i])  # prepend ! to non-empty error messages
     cat('', e, file = logfile, sep = '\n', append = TRUE)
diff --git a/R/utils.R b/R/utils.R
index c498c298d..8497ce87a 100644
--- a/R/utils.R
+++ b/R/utils.R
@@ -19,4 +19,11 @@ xfun_session_info = function() {
   paste(c('LaTeX version used: ', paste0('  ', info)), collapse = '\n')
 }
 
-read_lines = function(...) readLines(..., warn = FALSE)
+# read a file without warning, and discard lines with invalid characters to
+# avoid warnings in the grep() family (invalid lines in log files should be safe
+# to discard in this package, although it isn't so in general)
+read_lines = function(...) {
+  x = readLines(..., warn = FALSE)
+  x[!validEnc(x)] = ''
+  x
+}