diff --git a/BizHawk.Client.EmuHawk/MainForm.cs b/BizHawk.Client.EmuHawk/MainForm.cs
index 6715d97a3c..7665af6360 100644
--- a/BizHawk.Client.EmuHawk/MainForm.cs
+++ b/BizHawk.Client.EmuHawk/MainForm.cs
@@ -1857,7 +1857,7 @@ namespace BizHawk.Client.EmuHawk
 				if (VersionInfo.DeveloperBuild)
 				{
 					return FormatFilter(
-						"Rom Files", "*.nes;*.fds;*.sms;*.gg;*.sg;*.pce;*.sgx;*.bin;*.smd;*.rom;*.a26;*.a78;*.lnx;*.m3u;*.cue;*.ccd;*.exe;*.gb;*.gbc;*.gba;*.gen;*.md;*.col;.int;*.smc;*.sfc;*.prg;*.d64;*.g64;*.crt;*.sgb;*.xml;*.z64;*.v64;*.n64;*.ws;*.wsc;*.dsk;%ARCH%",
+						"Rom Files", "*.nes;*.fds;*.sms;*.gg;*.sg;*.pce;*.sgx;*.bin;*.smd;*.rom;*.a26;*.a78;*.lnx;*.m3u;*.cue;*.ccd;*.exe;*.gb;*.gbc;*.gba;*.gen;*.md;*.col;.int;*.smc;*.sfc;*.prg;*.d64;*.g64;*.crt;*.sgb;*.xml;*.z64;*.v64;*.n64;*.ws;*.wsc;*.dsk;*.do;*.po;%ARCH%",
 						"Music Files", "*.psf;*.sid;*.nsf",
 						"Disc Images", "*.cue;*.ccd;*.m3u",
 						"NES", "*.nes;*.fds;*.nsf;%ARCH%",
@@ -1881,7 +1881,7 @@ namespace BizHawk.Client.EmuHawk
 						"SID Commodore 64 Music File", "*.sid;%ARCH%",
 						"Nintendo 64", "*.z64;*.v64;*.n64",
 						"WonderSwan", "*.ws;*.wsc;%ARCH%",
-						"Apple II", "*.dsk;%ARCH%",
+						"Apple II", "*.dsk;*.do;*.po;%ARCH%",
 						"All Files", "*.*");
 				}
 
diff --git a/BizHawk.Emulation.Common/Database/Database.cs b/BizHawk.Emulation.Common/Database/Database.cs
index 5f28d9fb1f..44f9035e4e 100644
--- a/BizHawk.Emulation.Common/Database/Database.cs
+++ b/BizHawk.Emulation.Common/Database/Database.cs
@@ -341,6 +341,8 @@ namespace BizHawk.Emulation.Common
 					break;
 
 				case ".DSK":
+				case ".PO":
+				case ".DO":
 					game.System = "AppleII";
 					break;
 			}