diff --git a/chromeos/disks/disk_mount_manager.cc b/chromeos/disks/disk_mount_manager.cc
index ec19b3ddfcf346..a4caa57eb06c37 100644
--- a/chromeos/disks/disk_mount_manager.cc
+++ b/chromeos/disks/disk_mount_manager.cc
@@ -19,6 +19,7 @@
#include "base/macros.h"
#include "base/memory/ptr_util.h"
#include "base/memory/weak_ptr.h"
+#include "base/metrics/histogram_functions.h"
#include "base/observer_list.h"
#include "base/strings/string_util.h"
#include "chromeos/constants/chromeos_features.h"
@@ -555,6 +556,9 @@ class DiskMountManagerImpl : public DiskMountManager,
DiskMap::const_iterator disk = disks_.find(device_path);
DCHECK(disk != disks_.end() && disk->second->mount_path().empty());
+ base::UmaHistogramEnumeration("FileBrowser.FormatFileSystemType",
+ filesystem);
+
const std::string filesystem_str = FormatFileSystemTypeToString(filesystem);
pending_format_changes_[device_path] = {filesystem_str, label};
diff --git a/chromeos/disks/disk_mount_manager.h b/chromeos/disks/disk_mount_manager.h
index 8e6d50b9020987..44dbde43a7931b 100644
--- a/chromeos/disks/disk_mount_manager.h
+++ b/chromeos/disks/disk_mount_manager.h
@@ -28,11 +28,14 @@ enum MountCondition {
};
// Possible filesystem types that can be passed to FormatMountedDevice.
+// These values are persisted to logs. Entries should not be renumbered and
+// numeric values should never be reused.
enum class FormatFileSystemType {
kUnknown = 0,
kVfat = 1,
kExfat = 2,
kNtfs = 3,
+ kMaxValue = kNtfs,
};
// This class handles the interaction with cros-disks.
diff --git a/tools/metrics/histograms/enums.xml b/tools/metrics/histograms/enums.xml
index d3b85e3161fee3..584f8ae80ddb63 100644
--- a/tools/metrics/histograms/enums.xml
+++ b/tools/metrics/histograms/enums.xml
@@ -25025,6 +25025,13 @@ Called by update_net_error_codes.py.-->
+
+
+
+
+
+
+
diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
index f2c066c4e5d9e1..4c56a8705f11cf 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -43964,6 +43964,15 @@ uploading your change for review.
+
+ austinct@chromium.org
+
+ Chrome OS File Browser: this records the filesystem selected when formatting
+ an external drive.
+
+
+