diff --git a/www/manager6/Utils.js b/www/manager6/Utils.js
index 7ca6a271..adcf082f 100644
--- a/www/manager6/Utils.js
+++ b/www/manager6/Utils.js
@@ -1569,7 +1569,58 @@ Ext.define('PVE.Utils', {
 	}
     },
 
-    hardware_counts: { net: 32, usb: 5, hostpci: 16, audio: 1, efidisk: 1, serial: 4, rng: 1, tpmstate: 1 },
+    hardware_counts: {
+	net: 32,
+	usb: 14,
+	usb_old: 5,
+	hostpci: 16,
+	audio: 1,
+	efidisk: 1,
+	serial: 4,
+	rng: 1,
+	tpmstate: 1,
+    },
+
+    // we can have usb6 and up only for specific machine/ostypes
+    get_max_usb_count: function(ostype, machine) {
+	if (!ostype) {
+	    return PVE.Utils.hardware_counts.usb_old;
+	}
+
+	let match = /-(\d+).(\d+)/.exec(machine ?? '');
+	if (!match || PVE.Utils.qemu_min_version([match[1], match[2]], [7, 1])) {
+	    if (ostype === 'l26') {
+		return PVE.Utils.hardware_counts.usb;
+	    }
+	    let os_match = /^win(\d+)$/.exec(ostype);
+	    if (os_match && os_match[1] > 7) {
+		return PVE.Utils.hardware_counts.usb;
+	    }
+	}
+
+	return PVE.Utils.hardware_counts.usb_old;
+    },
+
+    // parameters are expected to be arrays, e.g. [7,1], [4,0,1]
+    // returns true if toCheck is equal or greater than minVersion
+    qemu_min_version: function(toCheck, minVersion) {
+	let i;
+	for (i = 0; i < toCheck.length && i < minVersion.length; i++) {
+	    if (toCheck[i] < minVersion[i]) {
+		return false;
+	    }
+	}
+
+	if (minVersion.length > toCheck.length) {
+	    for (; i < minVersion.length; i++) {
+		if (minVersion[i] !== 0) {
+		    return false;
+		}
+	    }
+	}
+
+	return true;
+    },
 
     cleanEmptyObjectKeys: function(obj) {
 	for (const propName of Object.keys(obj)) {
diff --git a/www/manager6/qemu/HardwareView.js b/www/manager6/qemu/HardwareView.js
index 6e9d03b4..96fd37e9 100644
--- a/www/manager6/qemu/HardwareView.js
+++ b/www/manager6/qemu/HardwareView.js
@@ -544,6 +544,11 @@ Ext.define('PVE.qemu.HardwareView', {
 
 	let counts = {};
 	let isAtLimit = (type) => counts[type] >= PVE.Utils.hardware_counts[type];
+	let isAtUsbLimit = () => {
+	    let ostype = me.getObjectValue('ostype');
+	    let machine = me.getObjectValue('machine');
+	    return counts.usb >= PVE.Utils.get_max_usb_count(ostype, machine);
+	};
 
 	let set_button_status = function() {
 	    let selection_model = me.getSelectionModel();
@@ -570,7 +575,7 @@ Ext.define('PVE.qemu.HardwareView', {
 	    const noVMConfigNetPerm = !caps.vms['VM.Config.Network'];
 	    const noVMConfigDiskPerm = !caps.vms['VM.Config.Disk'];
 
-	    me.down('#addUsb').setDisabled(noSysConsolePerm || isAtLimit('usb'));
+	    me.down('#addUsb').setDisabled(noSysConsolePerm || isAtUsbLimit());
 	    me.down('#addPci').setDisabled(noSysConsolePerm || isAtLimit('hostpci'));
 	    me.down('#addAudio').setDisabled(noVMConfigHWTypePerm || isAtLimit('audio'));
 	    me.down('#addSerial').setDisabled(noVMConfigHWTypePerm || isAtLimit('serial'));
diff --git a/www/manager6/qemu/USBEdit.js b/www/manager6/qemu/USBEdit.js
index 4373f82c..fe51d186 100644
--- a/www/manager6/qemu/USBEdit.js
+++ b/www/manager6/qemu/USBEdit.js
@@ -12,12 +12,17 @@ Ext.define('PVE.qemu.USBInputPanel', {
     setVMConfig: function(vmconfig) {
 	var me = this;
 	me.vmconfig = vmconfig;
+	let max_usb = PVE.Utils.get_max_usb_count(me.vmconfig.ostype, me.vmconfig.machine);
+	if (max_usb > PVE.Utils.hardware_counts.usb_old) {
+	    me.down('field[name=usb3]').setDisabled(true);
+	}
     },
 
     onGetValues: function(values) {
 	var me = this;
 	if (!me.confid) {
-	    for (let i = 0; i < PVE.Utils.hardware_counts.usb; i++) {
+	    let max_usb = PVE.Utils.get_max_usb_count(me.vmconfig.ostype, me.vmconfig.machine);
+	    for (let i = 0; i < max_usb; i++) {
 		let id = 'usb' + i.toString();
 		if (!me.vmconfig[id]) {
 		    me.confid = id;