A maskless lithography system for transferring a pattern onto a surface of a target, comprising: - at least one beamlet optical unit arranged to generate a plurality of beamlets, wherein said beamlet optical unit comprises a beamlet generator for generating a plurality of electron beamlets; - at least one measuring unit arranged to measure properties of each beamlet; - at least one control unit arranged to generate and deliver pattern data to said beamlet optical unit (3,5,6), said control unit being operationally coupled to said measuring unit such that, in use, invalid beamlets are identified, which have a measured property value outside a predefined range of values for said property, and said control unit being adapted to provide control signals to said beamlet optical unit such that, in use, the invalid beamlets are switched off when writing the pattern; - at least one actuator arranged to displace the surface of target and the beamlet optical unit with respect to one another, and to induce a shift of said beamlet optical unit and said target with respect to one another, wherein said actuator is operationally coupled with said control unit, said control unit being arranged to determine said shift, and position valid beamlets at the position of said invalid beamlets, such that, in use, said invalid beamlets are replaced with valid beamlets; said beamlet optical unit further comprising: - at least one scanner arranged to scan said beamlets over said surface in a scan direction, and - at least one modulator unit, aligned with said beamlets, and arranged to modulate the intensity of each of said beamlets, and wherein said control unit is operationally coupled to said modulator unit and said scanner such that, in use, pattern data is generated and delivered to said modulator unit and said scanner; wherein the maskless lithography system is configured to scan each of said plurality of beamlets over said surface by means of said scanner in said scan direction, while, in use, said target is advanced in a scanning direction other than said scan direction, the actuator being arranged to displace the beamlet optical unit with respect to the target surface in the scanning direction and to induce said shift in said scan direction; and wherein the maskless lithography system is configured such that, in use, after shifting, the beamlets are scanned over the surface once more, such that a scan line of a beamlet that is out of specification is written by a beamlet that is according to specification. - at least one beamlet optical unit arranged to generate a plurality of beamlets, wherein said beamlet optical unit comprises a beamlet generator for generating a plurality of electron beamlets; - at least one measuring unit arranged to measure properties of each beamlet; - at least one control unit arranged to generate and deliver pattern data to said beamlet optical unit (3,5,6), said control unit being operationally coupled to said measuring unit such that, in use, invalid beamlets are identified, which have a measured property value outside a predefined range of values for said property, and said control unit being adapted to provide control signals to said beamlet optical unit such that, in use, the invalid beamlets are switched off when writing the pattern; - at least one actuator arranged to displace the surface of target and the beamlet optical unit with respect to one another, and to induce a shift of said beamlet optical unit and said target with respect to one another, wherein said actuator is operationally coupled with said control unit, said control unit being arranged to determine said shift, and position valid beamlets at the position of said invalid beamlets, such that, in use, said invalid beamlets are replaced with valid beamlets; - at least one scanner arranged to scan said beamlets over said surface in a scan direction, and - at least one modulator unit, aligned with said beamlets, and arranged to modulate the intensity of each of said beamlets, and