Updated from June 12

Shares in Adobe Systems' ( ADBE) plunged more than 10% on Friday as the company's tepid guidance drew several downgrades and less-than-enthusiastic analyst reports.

The stock drop and the analyst reports followed the software maker's quarterly results on Thursday. Although Adobe beat Wall Street expectations, it warned that its third-quarter earnings will be below analysts' projections.

In issuing their negative reports on Adobe, analysts cited the summer quarter, typically a seasonally slow one for Adobe, as well as valuation concerns. Adobe's stock climbed 116% from early August to Thursday.

"At current price levels, we would encourage investors to take some profits," said Amy Feng, who covers Adobe for JMP Securities, in a report issued Friday. (JMP does not have investment-banking business with Adobe.)

In recent trading on Friday, shares in the software maker were off $4.18, or 11.62%, to $31.80.

Adobe's per-share earnings jumped 23% in the software makers' second quarter, despite nearly flat sales.

In its quarter ended May 30, Adobe earned $64.25 million, or 27 cents a share. That was up from the year-ago quarter, when the company earned $54.3 million, or 22 cents a share.

The company's overall revenues increased less than 1% year over year to $320.15 million.

The results beat analysts' expectations and came in at the high end of Adobe's guidance. But the company warned that it might not meet analysts' expectations in the current quarter.

Analysts polled by Thomson First Call were expecting the company to earn 26 cents a share on $312.87 million in revenue. In March, Adobe projected it would earn between 24 cents and 27 cents a share in the second quarter on $300 million to $315 million in revenue. A month later, the company raised its guidance, saying that it expected to earn between 24 cents to 28 cents on revenue of $305 million to $320 million.

For its third quarter, San Jose, Calif.-based Adobe is projecting it will earn 22 cents to 25 cents a share on $300 million to $315 million in revenue. Wall Street is expecting the company to earn 26 cents a share on $309.02 million in the current quarter.

On the revenue side, Adobe reported a mixed bag in the second quarter. Sales of Adobe's products, its primary source of revenue, fell less than 1% in the quarter to $314.15 million. The drop came despite better-than-expected sales of the company's Acrobat program. During the quarter, Adobe released an updated version of Acrobat, which creates documents in Adobe's proprietary PDF format.

Adobe saw a sharp decline in its imaging products in the quarter. Sales of Photoshop and related programs fell to $95.3 million from $130.6 million in the year-ago quarter.

The company faced a tough comparison with last year, company officials said during a conference call with analysts. Last year's sales of imaging products were boosted by the release of an updated version of Photoshop, they said.

While overall product sales stagnated in the quarter, Adobe saw a big jump in revenue from services and support. Such revenue increased to $6 million from $1.1 million.

As with its revenue, Adobe also reported a mixed performance on its expenses. Its gross profit margin, the difference between what it charges customers for its products and services and the direct costs involved in producing those products and services, increased 62 basis points to 92.7% of sales.

But that improvement was slightly outweighed by an increase in the company's operating expenses. Such expenses increased 69 basis points to 64.14% of sales.

The runup in Adobe's stock price in recent months was likely driven by the recent releases of the Photoshop and Acrobat upgrades, said Smith Barney analyst Craig Ellis in a report issued Thursday. Expectations of the success of those upgrades has now pushed Adobe's valuation to a peak level, indicating that the time has come to sell, he said.

"Current valuation levels have proven unsustainable for multiyear periods," Ellis wrote. "We believe it is time to lighten positions." (Smith Barney does not have any investment-banking business with Adobe.)

But not everyone agreed with that assessment. Several analysts maintained favorable ratings on Adobe. Many cited their expectations of continued strength in the company's Acrobat sales, as well as a projected upgrade of the company's Photoshop program later this year.

Baird analyst Steven Ashley reduced his price target from $42 to $40 a share. But he maintained his outperform rating on Adobe's stock.

"While guidance for (the third quarter) was below consensus expectations, the fact remains Adobe has beaten revenues and earnings guidance in each of the past two quarters, and has a history of underpromising and overdelivering," Ashley wrote in a report issued Friday.

"While seasonal softness in (the third quarter) will create a temporary dearth in Adobe's growth, we do not believe this has really altered our investment thesis. We still believe growth should resume in (the fourth quarter), and continue into next year." (Baird does not have investment-banking business with Adobe.)