Microsoft has halted distribution of a tool aimed at making it easier to put Windows 7 on Netbooks amid allegations that the utility makes improper use of open-source code. The software maker said on Tuesday that it has pulled down the Windows USB/DVD Tool while it investigates the issue, which was raised last week by Windows blogger Rafael Rivera on his Within Windows blog. In his blog post, Rivera said Microsoft appears to use code that is licensed under the GPL open-source license without providing back its modifications, among other issues. Microsoft confirmed it has launched a review of the matter and taken the utility off its online Microsoft Store until that inquiry has been completed. “Microsoft is looking into this issue and is taking down the (Windows 7 updating) tool from the Microsoft Store site until its review is complete,” the company said in a statement. “We apologize to our customers for any inconvenience.”

Though somewhat arcane, the utility is important because it solves a technical challenge in upgrading the operating system on Netbooks and other PCs without an optical drive. Microsoft had been exploring for months different ways of trying to help users of Windows XP-based Netbooks move to Windows 7. The tool, which was released last month alongside Windows 7, allows users to take a downloadable copy of the operating system and create a bootable drive. The issue is also a thorn in Microsoft’s efforts to show that it can play nice with the open-source community. As ZDNet blogger Mary Jo Foley notes, this isn’t the first time Microsoft has been accused of misusing GPL code.