When the French invaded in 1757 Wesel was evacuated, leaving Geldern isolated. Although surrounded, the fortress was well protected by flooding and was defended successfully until August 23rd. An attempt by what have been described as "unreliable foreigners" in the regiment to mutiny and surrender the place was foiled (Dorn and Engelmann) but food eventually ran out and Colonel von Salmuth commanding was able to agree terms of surrender with the French which included free departure for the regiment. When they left, most of the men deserted, leaving only fifteen officers, eighteen NCOs, twenty four privates, one drummer and five flags to reach Magdeburg. On October 13th they marched to Berlin, arriving just in time to withdraw to Potsdam in the face of the Austrian general Hadik's attack on Berlin. In spring 1758 the battalion was sent back to Magdeburg to act as garrison. In 1763 at the end of the war it returned to Geldern and combined with Salenmon's Freikorps to make a total of two battalions.
The grenadiers of the regiment were combined with the grenadiers of Garrison Regiment XIII and IR45 to form Standing Grenadier Battalion No.II. They had a rough war. Having been part of Frederick's invasion force of Saxony in 1756 which surrounded the Saxons at Pirna, they then took part in the invasion of Bohemia in 1757. They were at Prague in May that year, then the defeat at Moys in September. Having been badly chopped up there they were temporarily amalgamated with Grenadier Battalion 41/44 until the spring of 1758. In November 1757 they were at Breslau as right flank guard. At Leuthen in December they were again part of the refused right flank guard. At Hochkirch in October 1758 the battalion was on the extreme left of the Prussian position and was overwhelmed by the Austrian corps of Arenberg, losing two of its companies as prisoners. After the battle the battalion was once again amalgamated with Grenadier Battalion 41/44. (Duffy shows total losses of over 70% for the battalion at Hochkirch (Duffy, Army of Frederick the Great, 1st Edition).) As the final indignity, the entire battalion was captured at Glatz in July 1760. By then there was no longer any prisoner exchange with the Austrians so the battalion was not re-established before the end of the war.
The regimental flag design is shown at the top (Kompaniefahnen), the Colonel's flag (or Leibfahne) at the bottom.
