diff --git a/main.cpp b/main.cpp
index 2230b16a..28f98409 100644
--- a/main.cpp
+++ b/main.cpp
@@ -335,6 +335,7 @@ static void merge(struct mergelist *merges, size_t nmerges, unsigned char *map,
 		*progress += (ix.end - ix.start) * 3 / 4;
 		if (!quiet && !quiet_progress && progress_time() && 100 * *progress / *progress_max != *progress_reported) {
 			fprintf(stderr, "Reordering geometry: %lld%% \r", 100 * *progress / *progress_max);
+			fflush(stderr);
 			*progress_reported = 100 * *progress / *progress_max;
 		}
 
@@ -795,6 +796,7 @@ void radix1(int *geomfds_in, int *indexfds_in, int inputs, int prefix, int split
 				*progress += (ix.end - ix.start) / 4;
 				if (!quiet && !quiet_progress && progress_time() && 100 * *progress / *progress_max != *progress_reported) {
 					fprintf(stderr, "Reordering geometry: %lld%% \r", 100 * *progress / *progress_max);
+					fflush(stderr);
 					*progress_reported = 100 * *progress / *progress_max;
 				}
 
@@ -967,6 +969,7 @@ void radix1(int *geomfds_in, int *indexfds_in, int inputs, int prefix, int split
 					*progress += (ix.end - ix.start) * 3 / 4;
 					if (!quiet && !quiet_progress && progress_time() && 100 * *progress / *progress_max != *progress_reported) {
 						fprintf(stderr, "Reordering geometry: %lld%% \r", 100 * *progress / *progress_max);
+						fflush(stderr);
 						*progress_reported = 100 * *progress / *progress_max;
 					}
 
@@ -1787,6 +1790,7 @@ std::pair<int, metadata> read_input(std::vector<source> &sources, char *fname, i
 	if (!quiet) {
 		fprintf(stderr, "                              \r");
 		//     (stderr, "Read 10000.00 million features\r", *progress_seq / 1000000.0);
+		fflush(stderr);
 	}
 
 	for (size_t i = 0; i < CPUS; i++) {
@@ -2004,6 +2008,7 @@ std::pair<int, metadata> read_input(std::vector<source> &sources, char *fname, i
 				progress = nprogress;
 				if (!quiet && !quiet_progress && progress_time()) {
 					fprintf(stderr, "Maxzoom: %lld%% \r", progress);
+					fflush(stderr);
 				}
 			}
 		}
@@ -2178,6 +2183,7 @@ std::pair<int, metadata> read_input(std::vector<source> &sources, char *fname, i
 				progress = nprogress;
 				if (!quiet && !quiet_progress && progress_time()) {
 					fprintf(stderr, "Base zoom/drop rate: %lld%% \r", progress);
+					fflush(stderr);
 				}
 			}
 
diff --git a/pmtiles_file.cpp b/pmtiles_file.cpp
index 47fcba86..5de7d844 100644
--- a/pmtiles_file.cpp
+++ b/pmtiles_file.cpp
@@ -200,6 +200,7 @@ void mbtiles_map_image_to_pmtiles(char *fname, metadata m, bool tile_compression
 			pmtiles::zxy zxy = pmtiles::tileid_to_zxy(tile_id);
 			if (!quiet && !quiet_progress) {
 				fprintf(stderr, "  %3.1f%%  %d/%u/%u  \r", progress, zxy.z, zxy.x, zxy.y);
+				fflush(stderr);
 			}
 			sqlite3_bind_int(map_stmt, 1, zxy.z);
 			sqlite3_bind_int(map_stmt, 2, zxy.x);
diff --git a/serial.cpp b/serial.cpp
index 816fe735..da447277 100644
--- a/serial.cpp
+++ b/serial.cpp
@@ -713,6 +713,7 @@ int serialize_feature(struct serialization_state *sst, serial_feature &sf) {
 		checkdisk(sst->readers);
 		if (!quiet && !quiet_progress && progress_time()) {
 			fprintf(stderr, "Read %.2f million features\r", *sst->progress_seq / 1000000.0);
+			fflush(stderr);
 		}
 	}
 	(*(sst->progress_seq))++;
diff --git a/tile-join.cpp b/tile-join.cpp
index beac9124..f72c059d 100644
--- a/tile-join.cpp
+++ b/tile-join.cpp
@@ -588,6 +588,7 @@ void handle_tasks(std::map<zxy, std::vector<std::string>> &tasks, std::vector<st
 		if (ai == tasks.begin()) {
 			if (!quiet) {
 				fprintf(stderr, "%lld/%lld/%lld  \r", ai->first.z, ai->first.x, ai->first.y);
+				fflush(stderr);
 			}
 		}
 	}
diff --git a/tile.cpp b/tile.cpp
index 90330396..f03f5ea5 100644
--- a/tile.cpp
+++ b/tile.cpp
@@ -1436,6 +1436,7 @@ serial_feature next_feature(FILE *geoms, std::atomic<long long> *geompos_in, int
 		if (progress >= *oprogress + 0.1) {
 			if (!quiet && !quiet_progress && progress_time()) {
 				fprintf(stderr, "  %3.1f%%  %d/%u/%u  \r", progress, z, tx, ty);
+				fflush(stderr);
 			}
 			if (logger.json_enabled && progress_time()) {
 				logger.progress_tile(progress);
@@ -2562,6 +2563,7 @@ long long write_tile(FILE *geoms, std::atomic<long long> *geompos_in, char *stri
 		if (progress >= oprogress + 0.1) {
 			if (!quiet && !quiet_progress && progress_time()) {
 				fprintf(stderr, "  %3.1f%%  %d/%u/%u  \r", progress, z, tx, ty);
+				fflush(stderr);
 			}
 			if (logger.json_enabled && progress_time()) {
 				logger.progress_tile(progress);