Question: On June 6th, what prevented the Panzer division commanders from moving?
About the article "Invasion of Normandy", section "Armoured reserves".

Candidate passages:
The 16th Panzer Division crossed the River Bug immediately behind the 11th Panzer Division in the area of Sokal (in Poland in 1941, now in Ukraine), as part of the First Panzer Group (von Kleist) in von Rundstedt’s Army Group South.
The First Panzer Group drove its armoured spearhead of 600 tanks right through the Soviet 6th Army with the objective of capturing Brody.
On 26 June five Soviet mechanized corps with over 1,000 tanks mounted a counter-attack on the First Panzer Group.
The Battle of Brody/Rovno was among the fiercest of the invasion lasting over four days; in the end the Germans prevailed, though the Soviets inflicted heavy losses on the First Panzer Group, and themselves suffered huge tank losses – up to 243 reported to have been destroyed by Sieckenius’ 2 Panzer Regiment, in what was the world’s largest tank battle before the Battle of Kursk.
For this action Sieckenius was awarded the coveted Knight’s Cross.
The Panzer Group moved quickly on, linking up with the 17th Field Army to encircle Uman and capturing 20 Soviet divisions and over 100,000 men, including two Army commanders, four corps commanders and eleven divisional commanders.
Further swift advances were made, with Kiev being encircled on 16 September 1941 when Guderian’s XXIV Corps linked up with the First Panzer Group at Lokhvitsa, 120 miles east of Kiev.
A further 450,000 soviet prisoners were taken, and four armies had ceased to exist.
Complete breakthrough had now been achieved in the southern sector.
Having been delayed by the Battle of Kiev, Hitler now focused his effort on Moscow (Operation Typhoon), to where the attention of Army Groups North and Centre were switched.
Meanwhile in the south 16 Panzer Division, still under the First Panzer Group, advanced from Kiev, and encircled Soviet troops at Melitopol in October, then attacked east along the shore of the Sea of Azov toward Rostov at the mouth of the River Don - the gateway to the Caucasus.
Although slowed by rains and Soviet defence, the Panzer Group reached Rostov on 17 November 1941, capturing the city (Battle of Rostov) four days later.
A Russian counter-offensive on 27 November recaptured the city and pushed the Germans back to Taganrog, the first German reversal of the Eastern Front. 
On June 22nd, 1941, the first day of the German invasion, orders went out from headquarters Southwestern Front under Mikhail Kirponos to the mechanized corps to deploy forward as quickly as possible.
The 9th Mechanized Corps moved its units towards the town of Irkutsk, into the path of the advancing 14th Panzer Division, which pushed the 131st Motorized Division out of the town.
Meanwhile, south of Irkutsk, the 11th Panzer Division secured Dubno, a vital road hub, against minimal resistance, and Kirponos ordered an immediate counter-attacked to retake it.
Although still in the process of moving forward towards the battle zone, both the 20th and 35th assembled forward detachments of between 30-40 tanks together with what infantry was to hand, and launched them forward, cutting the Irkutsk-Dubno road.
At the same time, elements of 19th Mechanized Corps' 43rd Tank Division recaptured Dubno.
The German reaction was swift; the next day, June 26th, the 13th Panzer Division struck down from Irkutsk, catching the 9th Mechanized forward detachments in the flank, rolling them up and sending then reeling back, whilst German infantry opened up the 11th Panzer supply rout by recapturing Dunbo.
The 13th Panzer turned east, and along secondary roads, took Rovno in the 9th's Mechanized rear.
However, on June 29th, the 14th Panzer, attempting to advance eastward along the main tank highway, was stopped cold by the 20th Tank Division, and was just able to hold Lutsh against "massive attacks".
The corps commander, Konstantin Rokossovsky, later wrote of this engagement in his memoirs, "The terrain off road was wooded and swampy, keeping the German advance to the road.
The artillery Regiment of the 20th Tank Division deployed its newly issued 85mm Guns to cover the road and with direct fire repulsed the advancing Panzers".
The 14th Panzer abandoned this route and followed the 13th Panzer Division.
Both Panzer divisions of III Panzer Corps pushed on, leaving 25th Panzergrenadier Division to protect their rear against repeated attacks by 9th Mechanized Corps to drive into Rovno.
The 25th Panzergrenadier Division reported extreme difficulty in holding back the attacks and suffered "serious losses" in the process.
By the beginning of July, German armor had smashed a hole in the center of the Russian line, and the 13th Panzer stood at the edge of the Kiev fortified district.
In another attempt to restore the front, Kirponos ordered attacks from the 5th Army in the north and 6th Army in the south to accomplish this aim.
The army still had three mechanized corps under command: the 9th, the 19th, and the 22nd.
The 5th Army forces lunged southward and managed to cut the Zhitomir - Kiev highway, blocking III Panzer Corps' supply lines.
The Germans reacted by assigning infantry to clear the road and push the Russians back to the north.
On the 9th of July, the corps was still in the Kiev Special Military District as part of the General reserve. 
Final orders of battle (after the Vienna Offensive).
German and German allied forces.
On 30 April, the following order of battle was recorded by the German Army High Command ("Oberkommando der Wehrmacht", or OKW).
From 20 April-2 May, OKW moved from Zossen (near Berlin) to Mürwik (part of Flensburg in north Germany, near Denmark).
This order of battle shows what remained "on paper" of the German armies that fought in Hungary and Austria.
German 6th SS Panzer Army – east of Linz *117th Jäger Division (arriving) *I SS Panzer Corps **1st SS Panzer Division **356th Infantry Division **12th SS Panzer Division **710th Infantry Division *II SS Panzer Corps **3rd SS Panzer Division **Fuehrer-Grenadier Division German 6th Army – north of Graz *IV SS Panzer Corps **3rd Panzer Division **5th SS Panzer Division **14th SS Grenadier Division *III Panzer Corps **1st People's Mountain Infantry Division **1st Panzer Division German 2nd Panzer Army – south of Graz (near Maribor) *LXVIII Corps **71st Infantry Division **13th SS Alpine Division **118th Jäger Division *XXII Mountain Corps **297th Infantry Division **Hungarian Szent László Infantry Division *I Cavalry Corps **23rd Panzer Division **4th Cavalry Division **3rd Cavalry Division **16th SS Panzergrenadier Division  
In the first days of June, Beauman Division continued to construct what defences it could along the 55 mile Andelle-Béthune line.
On 6 June they were reinforced by a further three battalions of infantry; some artillery and engineer units arrived in the following days.
However, "A" Brigade was detached from line to assist the 51st (Highland) Division; (it became part of Ark force which was formed to cover the retirement of the Highlanders towards Le Havre).
Some units of 1st Armoured Division arrived in support, but remained under the orders of the Tenth Army commander, General Altmayer.
The difficulty of maintaining communications led General Beauman to issue orders that units would hold on ""as long as any hope of successful resistance remained"" and that ""Brigade commanders will use their discretion as regards withdrawal"".
At dawn on 8 June, the 5th and 7th Panzer Divisions renewed their drive towards Rouen.
The first German attacks were at Forges-les-Eaux and Sigy-en-Bray.
At Forges, refugees prevented the planned blocking of roads and when French tanks appeared, they were allowed to pass through.
However, they had been captured by the Germans and once through the road blocks, attacked the British positions from the rear.
The units of the division were pushed back and the line was penetrated in many places, despite the support of 1st Armoured Division on their left.
Late in the afternoon, Syme's Battalion, only formed from depot troops in the previous week, held up 5th Panzer for several hours outside Rouen before being forced to retire.
During the night, the remainder of the division retired across the Seine. 
At the time of the counterattack, Manstein could count on the Fourth Panzer Army, composed of XLVIII Panzer Corps, the SS Panzer Corps and the First Panzer Army, with the XL and LVII Panzer Corps.
The XLVIII Panzer Corps was composed of the 6th, 11th and 17th Panzer Divisions, while the SS Panzer Corps was organized with the 1st SS, 2nd SS and 3rd SS Panzer Division.
In early February, the combined strength of the SS Panzer Corps was an estimated 20,000 soldiers.
The Fourth Panzer Army and the First Panzer Army were situated south of the Red Army's bulge into German lines, with the First Panzer Army to the east of the Fourth Panzer Army.
The SS Panzer Corps was deployed along the northern edge of the bulge, on the northern front of Army Group South.
The Germans were able to amass around 70,000 men against the 210,000 Red Army soldiers.
The German "Wehrmacht" was understrength, especially after continuous operations between June 1942 and February 1943, to the point where Hitler appointed a committee made up of Field Marshal Wilhelm Keitel, Martin Bormann and Hans Lammers, to recruit 800,000 new able-bodied men—half of whom would come from "nonessential industries".
However, the effects of this recruitment were not seen until around May 1943, when the German armed forces were at their highest strength since the beginning of the war, with 9.5 million personnel.
By the start of 1943 Germany's armored forces had sustained heavy casualties.
It was unusual for a Panzer Division to field more than 100 tanks, and most averaged only 70–80 serviceable tanks at any given time.
After the fighting around Kharkov, Heinz Guderian embarked on a program to bring Germany's mechanized forces up to strength.
Despite his efforts, a German panzer division could only count on an estimated 10,000–11,000 personnel, out of an authorized strength of 13,000–17,000.
Only by June did a panzer division begin to field between 100–130 tanks each.
SS divisions were normally in better shape, with an estimated 150 tanks, a battalion of self-propelled assault guns and enough half-tracks to motorize most of its infantry and reconnaissance soldiers—and these had an authorized strength of an estimated 19,000 personnel.
At this time, the bulk of Germany's armor was still composed of Panzer IIIs and Panzer IVs, although the 2nd SS Panzer Division had been outfitted with a number of Tiger I tanks.
The Fourth Panzer Army was commanded by General Hermann Hoth, while the First Panzer Army fell under the leadership of General Eberhard von Mackensen.
The 6th, 11th and 17th Panzer Divisions were commanded by Generals Walther von Hünersdorff, Hermann Balck and Fridolin von Senger und Etterlin, respectively.
The SS Panzer Corps was commanded by General Paul Hausser, who also had the 3rd SS Panzer (Totenkopf) Division under his command.