Process for preparing a double metal cyanide catalyst (DMC) comprising i) reaction of an aqueous solution of a cyanide-free metal salt, an aqueous solution of a metal cyanide salt, an organic complex ligand, optionally a complex-forming component, to form a dispersion; (ii) separation of the solid off from the dispersion obtained from (i); (iii) washing of the isolated solid by means of redispersion or filtercake washing, (iv) drying of the solid obtained, wherein the reaction in step i) is effected using a mixing nozzle, wherein the organic complex ligand is one or more compound(s) and is selected from the group consisting of dimethoxyethane, tert-butanol, 2-methyl-3-buten-2-ol, 2-methyl-3-butyn-2-ol, ethylene glycol mono-tert-butyl ether and 3-methyl-3-oxetanemethanol, preferably tert-butanol, wherein double metal cyanide compounds of the formula (I) are present in the DMC catalyst M x [M' x ,(CN) y ] z (I), where M is selected from one or more metal cations from the group consisting of Zn(II), Fe(II), Ni(II), Mn(II), Co(II), Sr(II), Sn(II), Pb(II) and Cu(II), preferably Zn(II), Fe(II), Co (II) and Ni(II), and M' is selected from one or more metal cations from the group consisting of Fe(II), Fe(III), Co(II), Co(III), Cr(II), Cr(III), Mn(II), Mn(III), Ir(III), Ni(II), Rh(III), Ru(II), V(IV) and V(V), preferably Co(III), Fe(III), Cr(III) and Ir(III), and x, x', y and z are integers and are selected such as to ensure the electronic neutrality of the double metal cyanide compound, preferably x = 3, x' = 1, y = 6 and z = 2, characterized in that the reaction in step i) is effected in the presence of a peroxide. i) reaction of an aqueous solution of a cyanide-free metal salt, an aqueous solution of a metal cyanide salt, an organic complex ligand, optionally a complex-forming component, to form a dispersion; (ii) separation of the solid off from the dispersion obtained from (i); (iii) washing of the isolated solid by means of redispersion or filtercake washing, (iv) drying of the solid obtained, wherein the reaction in step i) is effected using a mixing nozzle, wherein the organic complex ligand is one or more compound(s) and is selected from the group consisting of dimethoxyethane, tert-butanol, 2-methyl-3-buten-2-ol, 2-methyl-3-butyn-2-ol, ethylene glycol mono-tert-butyl ether and 3-methyl-3-oxetanemethanol, preferably tert-butanol, wherein double metal cyanide compounds of the formula (I) are present in the DMC catalyst M x [M' x ,(CN) y ] z (I), where M is selected from one or more metal cations from the group consisting of Zn(II), Fe(II), Ni(II), Mn(II), Co(II), Sr(II), Sn(II), Pb(II) and Cu(II), preferably Zn(II), Fe(II), Co (II) and Ni(II), and M' is selected from one or more metal cations from the group consisting of Fe(II), Fe(III), Co(II), Co(III), Cr(II), Cr(III), Mn(II), Mn(III), Ir(III), Ni(II), Rh(III), Ru(II), V(IV) and V(V), preferably Co(III), Fe(III), Cr(III) and Ir(III), and x, x', y and z are integers and are selected such as to ensure the electronic neutrality of the double metal cyanide compound, preferably x = 3, x' = 1, y = 6 and z = 2, characterized in that the reaction in step i) is effected in the presence of a peroxide. M is selected from one or more metal cations from the group consisting of Zn(II), Fe(II), Ni(II), Mn(II), Co(II), Sr(II), Sn(II), Pb(II) and Cu(II), preferably Zn(II), Fe(II), Co (II) and Ni(II), and M' is selected from one or more metal cations from the group consisting of Fe(II), Fe(III), Co(II), Co(III), Cr(II), Cr(III), Mn(II), Mn(III), Ir(III), Ni(II), Rh(III), Ru(II), V(IV) and V(V), preferably Co(III), Fe(III), Cr(III) and Ir(III), and x, x', y and z are integers and are selected such as to ensure the electronic neutrality of the double metal cyanide compound, preferably x = 3, x' = 1, y = 6 and z = 2, characterized in that the reaction in step i) is effected in the presence of a peroxide. <EOS>