Microsoft saw its smartphone market share decline in the three-month period ending in June, according to research firm comScore.

According to eWeek, specifically, the company saw its share decline from 7.5 percent to 5.8 percent, over a period when both archrivals Google and Apple experienced gains. Research In Motion also dipped, from 27.1 percent to 23.4 percent.

ComScore also listed the top mobile OEMs, in descending order, as Samsung, LG Electronics, Motorola, Apple and RIM. Of those, Motorola and RIM experienced incremental declines, while the rest enjoyed equally slight gains.

Microsoft’s market share included both its antiquated Windows Mobile platform and the newer Windows Phone, which was supposed to reinvigorate the company’s fortunes in the smartphone space. Instead, Windows Phone is showing signs of anemic adoption by consumers and businesses. According to data from Nielsen, Microsoft occupied some 9 percent of the U.S. smartphone market in June - trailing Google Android with 39 percent, Apple’s iPhone with 28 percent and RIM with 20 percent, Nicholas Kolakowski writes.

Microsoft is hoping that its upcoming “Mango” update, which supposedly includes some 500 new tweaks and features, will help spur Windows Phone adoption. Mango reached its Release to Manufacturing milestone July 26.

Samsung, HTC, LG Electronics and Nokia have all committed to building new Windows Phone devices preloaded with Mango, along with Acer and ZTE.