Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Affordable 16GB SDHC card that just stopped working after 4 months

I wanted a reliable 16 GB SDHC card to create an emergency bootable disk for my MacBook Pro. This one provides enough space for the operating system (without the printer drivers and language support) and some additional diagnostic tools. I also purchased a second one to use with Time Machine. The big but is that after four months of minimal use they both just stopped working. I was unable to access them with my Mac or with file recovery software or even reformat them. Would strongly recommend a more reliable brand.