diff --git a/res/appstore/Package.appxmanifest b/res/appstore/Package.appxmanifest
index 8dc06d2f..80b25f24 100644
--- a/res/appstore/Package.appxmanifest
+++ b/res/appstore/Package.appxmanifest
@@ -11,7 +11,7 @@
   <Identity
     Name="19453.net.Rufus"
     Publisher="CN=7AC86D13-3E5A-491A-ADD5-80095C212740"
-    Version="3.14.1798.0" />
+    Version="3.14.1799.0" />
 
   <Properties>
     <DisplayName>Rufus</DisplayName>
diff --git a/src/rufus.c b/src/rufus.c
index 6beb02f8..e4cfd714 100755
--- a/src/rufus.c
+++ b/src/rufus.c
@@ -2342,14 +2342,14 @@ static INT_PTR CALLBACK MainCallback(HWND hDlg, UINT message, WPARAM wParam, LPA
 				persistence_size = lPos * MB;
 				for (i = 0; i < persistence_unit_selection; i++)
 					persistence_size *= 1024;
-				if (persistence_size > SelectedDrive.DiskSize - img_report.projected_size)
-					persistence_size = SelectedDrive.DiskSize - img_report.projected_size;
+				if (persistence_size > SelectedDrive.DiskSize - PERCENTAGE(PROJECTED_SIZE_RATIO, img_report.projected_size))
+					persistence_size = SelectedDrive.DiskSize - PERCENTAGE(PROJECTED_SIZE_RATIO, img_report.projected_size);
 				pos = persistence_size / MB;
 				for (i = 0; i < persistence_unit_selection; i++)
 					pos /= 1024;
 				lPos = (LONG)pos;
 				SendMessage(GetDlgItem(hMainDialog, IDC_PERSISTENCE_SLIDER), TBM_SETPOS, TRUE, lPos);
-				if (persistence_size >= (SelectedDrive.DiskSize - img_report.projected_size)) {
+				if (persistence_size >= (SelectedDrive.DiskSize - PERCENTAGE(PROJECTED_SIZE_RATIO, img_report.projected_size))) {
 					static_sprintf(tmp, "%ld", lPos);
 					app_changed_size = TRUE;
 					SetWindowTextU(GetDlgItem(hMainDialog, IDC_PERSISTENCE_SIZE), tmp);
@@ -3185,6 +3185,14 @@ int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine
 		uprintf("Could not get current directory: %s", WindowsErrorString());
 		app_dir[0] = 0;
 	}
+	// Microsoft has a bad habit of making some of its APIs (_chdir/_wchdir) break
+	// when app_dir is a drive letter that doesn't have a trailing backslash. For
+	// instance _chdir("F:") does not change the directory, whereas _chdir("F:\\")
+	// does. So make sure we add a trailing backslash if the app_dir is a drive.
+	if ((app_dir[1] == ':') && (app_dir[2] == 0)) {
+		app_dir[2] = '\\';
+		app_dir[3] = 0;
+	}
 	if (GetSystemDirectoryU(system_dir, sizeof(system_dir)) == 0) {
 		uprintf("Could not get system directory: %s", WindowsErrorString());
 		static_strcpy(system_dir, "C:\\Windows\\System32");
diff --git a/src/rufus.h b/src/rufus.h
index dce00e6e..3258c3ff 100644
--- a/src/rufus.h
+++ b/src/rufus.h
@@ -79,6 +79,7 @@
 #define MAX_WININST                 4			// Max number of install[.wim|.esd] we can handle on an image
 #define MBR_UEFI_MARKER             0x49464555	// 'U', 'E', 'F', 'I', as a 32 bit little endian longword
 #define MORE_INFO_URL               0xFFFF
+#define PROJECTED_SIZE_RATIO        110			// Percentage by which we inflate projected_size to prevent persistence overflow
 #define STATUS_MSG_TIMEOUT          3500		// How long should cheat mode messages appear for on the status bar
 #define WRITE_RETRIES               4
 #define WRITE_TIMEOUT               5000		// How long we should wait between write retries (in ms)
@@ -129,6 +130,7 @@
 #ifndef STRINGIFY
 #define STRINGIFY(x)                #x
 #endif
+#define PERCENTAGE(percent, value)  ((1ULL * percent * value) / 100ULL)
 #define IsChecked(CheckBox_ID)      (IsDlgButtonChecked(hMainDialog, CheckBox_ID) == BST_CHECKED)
 #define MB_IS_RTL                   (right_to_left_mode?MB_RTLREADING|MB_RIGHT:0)
 #define CHECK_FOR_USER_CANCEL       if (IS_ERROR(FormatStatus) && (SCODE_CODE(FormatStatus) == ERROR_CANCELLED)) goto out
diff --git a/src/rufus.rc b/src/rufus.rc
index 9e64a037..35ef0422 100644
--- a/src/rufus.rc
+++ b/src/rufus.rc
@@ -33,7 +33,7 @@ LANGUAGE LANG_NEUTRAL, SUBLANG_NEUTRAL
 IDD_DIALOG DIALOGEX 12, 12, 232, 326
 STYLE DS_SETFONT | DS_MODALFRAME | DS_CENTER | WS_MINIMIZEBOX | WS_POPUP | WS_CAPTION | WS_SYSMENU
 EXSTYLE WS_EX_ACCEPTFILES
-CAPTION "Rufus 3.14.1798"
+CAPTION "Rufus 3.14.1799"
 FONT 9, "Segoe UI Symbol", 400, 0, 0x0
 BEGIN
     LTEXT           "Drive Properties",IDS_DRIVE_PROPERTIES_TXT,8,6,53,12,NOT WS_GROUP
@@ -395,8 +395,8 @@ END
 //
 
 VS_VERSION_INFO VERSIONINFO
- FILEVERSION 3,14,1798,0
- PRODUCTVERSION 3,14,1798,0
+ FILEVERSION 3,14,1799,0
+ PRODUCTVERSION 3,14,1799,0
  FILEFLAGSMASK 0x3fL
 #ifdef _DEBUG
  FILEFLAGS 0x1L
@@ -414,13 +414,13 @@ BEGIN
             VALUE "Comments", "https://rufus.ie"
             VALUE "CompanyName", "Akeo Consulting"
             VALUE "FileDescription", "Rufus"
-            VALUE "FileVersion", "3.14.1798"
+            VALUE "FileVersion", "3.14.1799"
             VALUE "InternalName", "Rufus"
             VALUE "LegalCopyright", "© 2011-2021 Pete Batard (GPL v3)"
             VALUE "LegalTrademarks", "https://www.gnu.org/licenses/gpl-3.0.html"
             VALUE "OriginalFilename", "rufus-3.14.exe"
             VALUE "ProductName", "Rufus"
-            VALUE "ProductVersion", "3.14.1798"
+            VALUE "ProductVersion", "3.14.1799"
         END
     END
     BLOCK "VarFileInfo"
diff --git a/src/ui.c b/src/ui.c
index b860cca0..5f480a56 100644
--- a/src/ui.c
+++ b/src/ui.c
@@ -726,7 +726,7 @@ void SetPersistenceSize(void)
 	uint64_t max = 0, pos = 0;
 
 	if (ComboBox_GetCurSel(hDeviceList) >= 0) {
-		max = SelectedDrive.DiskSize - img_report.projected_size;
+		max = SelectedDrive.DiskSize - PERCENTAGE(PROJECTED_SIZE_RATIO, img_report.projected_size);
 		persistence_size = min(persistence_size, max);
 		pos = persistence_size;